ON Semiconductor (ONNN)

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On August 5, 2009, ON Semiconductor Corporation (“Company”) announced in a news release its financial performance for the second quarter ended July 3, 2009 (“Earnings Release”). A copy of the Company’s Earnings Release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

On August 5, 2009, following the release of the Earnings Release, the Company will hold a live conference call at 5:00 p.m. Eastern time (ET) to discuss its financial performance for the quarter ended July 3, 2009. A copy of the script for this call is attached as Exhibit 99.2 and incorporated by reference. The call script includes certain non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable measures prepared in accordance with U.S. GAAP are set forth in the Company’s Earnings Release and posted separately on the Investor Relations page of the Company’s website at http://www.onsemi.com. The Company will provide a real-time audio broadcast of the teleconference on the Investor Relations page of its website at http://www.onsemi.com. The re-broadcast of the call will be available at this site approximately one hour following the live broadcast and will continue to be available for approximately 30 days following the conference call. Investors and interested parties can also access the conference call through a telephone call by dialing (888) 546-9664 (U.S./Canada) or (973) 935-8144 (International) and providing the conference ID number of 18498303. The Company will provide a dial-in replay approximately one hour following the live broadcast that will continue through approximately August 12, 2009. To listen to the teleconference replay, call (800) 642-1687 (U.S./Canada) or (706) 645-9291 (International). You will be required to provide the Conference ID Number – which is 18498303.

The information under this Item 2.02 of this report, including Exhibits 99.1 and 99.2, is being furnished under Item 2.02 and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (“Exchange Act”), or otherwise subject to liability of that section nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Not applicable.

Not applicable.

Not applicable.

The below exhibits are furnished as part of this report.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

EXHIBIT INDEX

The below exhibits are furnished as part of this report.

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On May 21, 2009, ON Semiconductor Corporation announced in a news release that it had recently repurchased approximately $34 million aggregate principal amount of its $260 million zero coupon convertible senior subordinated notes. A copy of the related news release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

Not applicable.

Not applicable.

Not applicable.

2

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

The following “Description of Common Stock” is filed for purposes of updating and superseding the description of the common stock of ON Semiconductor Corporation (the “Company”, “we”, “us”, “our”), contained in our registration statement on Form 8-A12G, filed with the Securities and Exchange Commission (the “Commission”) on April 21, 2000.

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On May 6, 2009, ON Semiconductor Corporation (“Company”) announced in a news release its financial performance for the first quarter ended April 3, 2009 and other related material information (“Earnings Release”). A copy of the Company’s Earnings Release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

On May 6, 2009, following the release of the Earnings Release, the Company will hold a live conference call at 5:00 p.m. Eastern time (ET) to discuss its financial performance for the quarter ended April 3, 2009 and other related material information. A copy of the script for this call is attached as Exhibit 99.2 and is incorporated herein by reference. The call script includes certain non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable measures prepared in accordance with U.S. GAAP are set forth in the Company’s Earnings Release and posted separately on the Investor Relations page of the Company’s website at http://www.onsemi.com. The Company will provide a real-time audio broadcast of the teleconference on the Investor Relations page of its website at http://www.onsemi.com. The re-broadcast of the call will be available at this site approximately one hour following the live broadcast and will continue to be available for approximately 30 days following the conference call. Investors and interested parties can also access the conference call through a telephone call by dialing (888) 546-9664 (U.S./Canada) or (706) 679-4331 (International) and providing the conference ID number of 95726971. The Company will provide a dial-in replay approximately one hour following the live broadcast that will continue through approximately May 13, 2009. To listen to the teleconference replay, call (800) 642-1687 (U.S./Canada) or (706) 645-9291 (International). You will be required to provide the Conference ID Number – which is 95726971.

The information under this Item 2.02 of this report, including Exhibits 99.1 and 99.2, is being furnished under Item 2.02 and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (“Exchange Act”), or otherwise subject to liability of that section nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Not applicable.

Not applicable.

Not applicable.

The below exhibits are furnished as part of this report.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

EXHIBIT INDEX

The below exhibits are furnished as part of this report.

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

ON Semiconductor Corporation (the “Corporation”) entered into privately negotiated exchanges with holders of the Corporation’s Zero Coupon Convertible Senior Subordinated Notes due 2024 (the “Notes”), pursuant to which the Corporation offered shares of its common stock, par value $0.01 per share (the “Common Stock”) and cash in exchange for the Notes. Between February 19, 2009 and April 1, 2009, the Corporation issued or expects to have issued an aggregate of 7,367,581 shares of its Common Stock and approximately $33 million in cash in exchange for $66 million in aggregate principal amount of the Notes. The Notes exchanged or planned to be exchanged represent approximately 33% of the $199.1 million of the Notes outstanding prior to the exchanges.

All shares of the Common Stock were issued without registration pursuant to the exemption provided in Section 3(a)(9) of the Securities Act of 1933, as amended. No commission or other remuneration was paid or given directly or indirectly for these transactions.

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On and effective February 26, 2009, the Board of Directors (“Board”) of ON Semiconductor Corporation (“Corporation”) elected Daryl Ostrander to serve as a Class I director of the Board. As a Class I director, Mr. Ostrander’s term will expire at the 2009 annual meeting of stockholders (or at such time as his successor is duly elected and qualified, or the earlier of his resignation, removal or disqualification) and his continued service on the Board will be voted on by the Corporation’s stockholders at the 2009 annual meeting of stockholders. In connection with his initial election, the Board did not appoint Mr. Ostrander to any Board committees. As a result of the appointment, Mr. Ostrander will be eligible under the Corporation’s compensation program for non-employee members of the Board (“Program”). Under this Program, Mr. Ostrander will receive the following compensation for his services as a director of our Board:

(1) Board Annual Retainer – An annual cash retainer payable to non-employee directors of $59,000 per year.

(2) Equity Compensation —

(a) Initial Directorship – Consistent with past practice, Mr. Ostrander was awarded a stock option to purchase 20,000 shares of the Corporation’s common stock, with equal pro rata vesting over a three year period beginning on the first anniversary of the grant date, at an exercise price equal to the fair market value of the stock on the grant date, and subject to the Corporation’s 2000 Stock Incentive Plan and a relevant stock option award agreement. Pursuant to the Corporation’s grant date policy, the grant date of the option will be March 2, 2009.

(b) Annual Director’s Award – Our non-employee directors also typically receive an annual equity-based award. Along with other non-employee directors, Mr. Ostrander was awarded restricted stock, which will be issued in an amount equal to $106,500 divided by the closing price of our common stock on the effective date of the grant, March 2, 2009, and which will vest on that date if Mr. Ostrander continues to be a director of the Company on that date. This award will also be subject to the Corporation’s 2000 Stock Incentive Plan and relevant award agreement.

(3) Other — Under the Program, Mr. Ostrander will not receive any cash meeting fees for attending Board or committee meetings since the Program provides (generally) that all directors will receive no cash meeting fees for attending Board or committee meetings. Mr. Ostrander will be reimbursed for reasonable expenses to attend Board and committee meetings and to perform other relevant Board duties. Except as described above, Mr. Ostrander will not receive any additional compensation for his services as a member of the Board.

Attached to this Current Report, as Exhibit 99.1, is a copy of the Corporation’s news release dated February 27, 2009 titled “Daryl Ostrander Joins the ON Semiconductor Board of Directors.”

On February 26, 2009, the Board also established Wednesday, May 20, 2009 as the date for the Corporation’s 2009 annual meeting of stockholders.

(c) Exhibits

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On February 4, 2009, ON Semiconductor Corporation (“Company”) announced in a news release its financial performance for the fourth quarter ended December 31, 2008 and other related material information (“Earnings Release”). A copy of the Company’s Earnings Release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

On February 4, 2009, following the release of the Earnings Release, the Company will hold a live conference call at 5:00 p.m. Eastern time (ET) to discuss its financial performance for the quarter ended December 31, 2008 and other related material information. A copy of the script for this call is attached as Exhibit 99.2 and incorporated by reference. The call script includes certain non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable measures prepared in accordance with U.S. GAAP are set forth in the Company’s Earnings Release and posted separately on the Investor Relations page of the Company’s website at http://www.onsemi.com. The Company will provide a real-time audio broadcast of the teleconference on the Investor Relations page of its website at http://www.onsemi.com. The re-broadcast of the call will be available at this site approximately one hour following the live broadcast and will continue to be available for approximately 30 days following the conference call. Investors and interested parties can also access the conference call through a telephone call by dialing (888) 546-9664 (U.S./Canada) or (706) 679-4331 (International) and providing the conference ID number of 82216241. The Company will provide a dial-in replay approximately one hour following the live broadcast that will continue through approximately February 11, 2009. To listen to the teleconference replay, call (800) 642-1687 (U.S./Canada) or (706) 645-9291 (International). You will be required to provide the Conference ID Number – which is 82216241.

The information under this Item 2.02 of this report, including Exhibits 99.1 and 99.2, is being furnished under Item 2.02 and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (“Exchange Act”), or otherwise subject to liability of that section nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Paragraph 6 of page 2 and carrying over to page 3 of the Earnings Release which describe certain cost reduction measures both committed to and announced by the Company on February 4, 2009, is hereby solely incorporated by reference into this Item 2.05.

Not applicable.

Not applicable.

Not applicable.

The below exhibits are furnished as part of this report.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

EXHIBIT INDEX

The below exhibits are furnished as part of this report.

(Registrant’s telephone number, including area code)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

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Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See definitions of “large accelerated filer,” “accelerated filer” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

The number of shares outstanding of the issuer’s class of common stock as of the close of business on October 24, 2008:

Table of Contents

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Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On October 30, 2008, ON Semiconductor Corporation (“Company”) announced in a news release its financial performance for the third quarter ended September 26, 2008 and other related material information (“Earnings Release”). A copy of the Company’s Earnings Release is attached hereto as Exhibit 99.1 and incorporated herein by reference.

On October 30, 2008, following the release of the Earnings Release, the Company will hold a live conference call at 5:00 p.m. Eastern time (ET) to discuss its financial performance for the quarter ended September 26, 2008 and other related material information. A copy of the script for this call is attached as Exhibit 99.2 and incorporated by reference. The call script includes certain non-GAAP financial measures. Reconciliations of these non-GAAP financial measures to the most directly comparable measures prepared in accordance with U.S. GAAP are set forth in the Company’s Earnings Release and posted separately on the Investor Relations page of the Company’s website at http://www.onsemi.com. The Company will provide a real-time audio broadcast of the teleconference on the Investor Relations page of its website at http://www.onsemi.com. The re-broadcast of the call will be available at this site approximately one hour following the live broadcast and will continue to be available for approximately 30 days following the conference call. Investors and interested parties can also access the conference call through a telephone call by dialing (888) 546-9664 (U.S./Canada) or (706) 679-4331 (International) and providing the conference ID number of 68319961. The Company will provide a dial-in replay approximately one hour following the live broadcast that will continue through approximately November 6, 2008. Listen to this replay by dialing (800) 642-1687 (U.S./Canada) or (706) 645-9291 (International) and providing the conference ID number of 68319961.

The information under this Item 2.02 of this report, including Exhibits 99.1 and 99.2, is being furnished under Item 2.02 and shall not be deemed to be “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, as amended (“Exchange Act”), or otherwise subject to liability of that section nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, or the Exchange Act, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Not applicable.

Not applicable.

Not applicable.

2

The below exhibits are furnished as part of this report.

3

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned thereunto duly authorized.

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EXHIBIT INDEX

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