UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

May 14, 2013

Date of Report (Date of earliest event reported)

DIODES INCORPORATED

(Exact name of registrant as specified in its charter)

(972) 987-3900

(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:

On May 14, 2013, the Company representatives attended J.P. Morgan 41^st Annual Global Technology, Media and Telecom Conference in Boston, Massachusetts and held a presentation meeting. A copy of the presentation slides is attached as Exhibit 99.1 to this Report.

The information in this Item 7.01, including Exhibit 99.1, will not be treated as filed for the purposes of Section 18 of the Securities Exchange Act of 1934 (the “Exchange Act”) or otherwise subject to the liabilities of that section. This information will not be incorporated by reference into a filing under the Securities Act of 1933, or into another filing under the Exchange Act, unless that filing expressly refers to specific information in this Report. The furnishing of the information in this Item 7.01 is not intended to, and does not, constitute a representation that such furnishing is required by Regulation FD or that the information in this Item 7.01 is material information that is not otherwise publicly available.

In the presentation, the Company utilized financial measures and terms not calculated in accordance with generally accepted accounting principles in the United States (“GAAP”) in order to provide stockholders with an alternative method for assessing our operating results in a manner that enables stockholders to more thoroughly evaluate our current performance as compared to past performance. We also believe these non-GAAP measures provide stockholders with a more informed baseline for modeling the Company’s future financial performance. Our management uses these non-GAAP measures for the same purpose. We believe that our stockholders should have access to, and that we are obligated to provide, the same set of tools that we use in analyzing our results. These non-GAAP measures should be considered in addition to results prepared in accordance with GAAP, but should not be considered a substitute for or superior to GAAP results. See Exhibit 99.1 to the Company’s Form 8-K, filed on May 14, 2013 for definitions of the non-GAAP financial measures, together with an explanation of why management uses these measures and why management believes that these non-GAAP financial measures are useful to stockholders. In addition, in Exhibit 99.1 to the Company’s Form 8-K, filed on May 14, 2013, we have provided tables to reconcile the non-GAAP financial measures utilized to GAAP financial measures.

Cautionary Information Regarding Forward-Looking Statements

Except for the historical and factual information contained in the press release attached as Exhibit 99.1, the matters set forth in the press release (including statements as to the expected benefits of the acquisition and other statements identified by words such as “estimates,” “expects,” “projects,” “plans,” “will” and similar expressions) are forward-looking statements within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. These forward-looking statements are subject to risks and uncertainties that may cause actual results to differ materially, including: the risk that BCD’s business will not be integrated successfully into the Company’s; the risk that the expected benefits of the acquisition may not be realized; the risk that BCD’s standards, procedures and controls will not be brought into conformance within the Company’s operations; difficulties coordinating the Company’s and BCD’s new product and process development, hiring additional management and other critical personnel, and increasing the scope, geographic diversity and complexity of the Company’s operations; difficulties in consolidating facilities and transferring processes and know-how; difficulties in reducing the costs of BCD’s business; the diversion of our management’s attention from the management of our business; the risk that we may not be able to maintain our current growth strategy or continue to maintain our current performance, costs and loadings in our manufacturing facilities; risks of domestic and foreign operations, including excessive operating costs, labor shortages, higher tax rates and our joint venture prospects; the risk of unfavorable currency exchange rates; our future guidance may be incorrect; the global economic weakness may be more severe or last longer than we currently anticipated; and the impact of competition and other risk factors relating to our industry and business as detailed from time to time in the Company’s reports filed with the SEC. You should not place undue reliance on these forward-looking statements, which speak only as of the date of the press release. The Company undertakes no obligation to update publicly any forward-looking statements, whether as a result of new information, future events or otherwise.

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 hereunto duly authorized.