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

Date of report (Date of earliest event reported) February 25, 2014

SBA Communications Corporation

(Exact Name of Registrant as Specified in its Charter)

Registrant’s telephone number, including area code: (561) 995-7670

(Former name or former address, if changed since last report)

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:

Item 2.02 Results of Operations and Financial Condition.

On February 25, 2014, SBA Communications Corporation (the “Company”) issued a press release announcing its financial and operational results for the fourth quarter and fiscal year ended December 31, 2013. The Company confirmed that it ended the period with 20,079 owned sites, which include wireless communications tower structures, rooftops and other structures that support antennas used for wireless communications. Of these sites, 14,886 are in the U.S. and its territories and 5,193 are in international markets (generating approximately 8.6% of total leasing revenue in the quarter). The press release also provided the Company’s first quarter 2014 guidance and updated its full year 2014 guidance. A copy of the press release is furnished as Exhibit 99.1.

The press release contains non-GAAP financial measures including (i) Site Leasing Segment Operating Profit, Site Development Segment Operating Profit, and Segment Operating Profit Margin; (ii) Tower Cash Flow and Tower Cash Flow Margin; (iii) Adjusted EBITDA, Annualized Adjusted EBITDA, and Adjusted EBITDA Margin; (iv) Net Debt, Net Secured Debt, Leverage Ratio, and Secured Leverage Ratio (collectively, our “Non-GAAP Debt Measures”); and (v) Funds from Operations (“FFO”), Adjusted Funds from Operations (“AFFO”), and AFFO per share.

We have included these non-GAAP financial measures because we believe that they provide investors additional tools in understanding our financial performance and condition. Specifically, we believe that:

(1) Segment Operating Profit is an indicator of the operating performance of our site leasing and site development segments;

(2) Tower Cash Flow is an indicator of the performance of our site leasing operations;

(3) Adjusted EBITDA, FFO, AFFO, and AFFO per share are useful indicators of the financial performance of our core businesses; and

(4) Our Non-GAAP Debt Measures provide investors a more complete understanding of our net debt and leverage position as they include the full principal amount of our debt which will be due at maturity.

In addition, Tower Cash Flow, Adjusted EBITDA, and our Non-GAAP Debt Measures are components of the calculations used by our lenders to determine compliance with certain covenants under our Senior Credit Agreement, 8.25% Notes, 5.625% Notes, and 5.75% Notes. These non-GAAP financial measures are not intended to be an alternative to any of the financial measures provided in our results of operations or our balance sheet as determined in accordance with GAAP.

We believe that FFO, AFFO, and AFFO per share, which are also being used by American Tower Corporation and Crown Castle International (our two public company peers in the communication site industry), provide investors useful indicators of the financial performance of our core business and permit investors an additional tool to evaluate the performance of our business against those of our two principal competitors. FFO, AFFO and AFFO per share are not necessarily indicative of the operating results that would have been achieved had we converted to a REIT. In addition, our FFO, AFFO, and AFFO per share may not be comparable to those reported in accordance with National Association of Real Estate Investment Trusts or by the other communication site companies as the calculation of these non-GAAP measures requires us to estimate the impact had we converted to a REIT, including estimates of the tax provision adjustment to reflect our estimate of our cash taxes had we been a REIT.

A reconciliation of each of these non-GAAP financial measures to their most directly comparable GAAP financial measures can be found in the press release.

Item 9.01 Financial Statements and Exhibits.

As described in Item 2.02 of this Current Report on Form 8-K, the following exhibit is furnished as part of this Current 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 hereunto duly authorized.

Date: February 26, 2014