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) January 21, 2015

AT&T INC.

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code (210) 821-4105

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 (see General Instruction A.2. below):

Item 1.01 Entry into a Material Definitive Agreement.

The disclosure under Item 2.03 is incorporated by reference in this Item 1.01.

Item 2.03 Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant.

On January 21, 2015, AT&T Inc. (“AT&T”) entered into a $9.155 billion credit agreement (the “Syndicated Credit Agreement”) containing a (i) $6.286 billion term loan facility (the “Tranche A Facility”) and a (ii) $2.869 billion term loan facility (the “Tranche B Facility”), with certain investment and commercial banks and Mizuho Bank, Ltd. (“Mizuho”), as administrative agent. AT&T also entered into a $2.0 billion 18-month credit agreement (the “18-Month Credit Agreement”) with Mizuho as initial lender and agent. In the event advances are made under either agreement, those advances would be used for general corporate purposes, including acquisition related payments. Amounts borrowed under the Tranche A Facility will be due and payable on the third anniversary of funding. Amounts borrowed under the Tranche B Facility will be subject to amortization from the third anniversary of funding, with twenty-five percent of the aggregate principal amount thereof being payable prior to the fifth anniversary thereof, and all remaining principal amount due and payable on such fifth anniversary. Amounts borrowed under the 18-Month Credit Agreement will be due and payable on the date that is 18 months after the funding.

The descriptions of the Syndicated Credit Agreement and the 18-Month Credit Agreement contained in this item 2.03 do not purport to be complete and are qualified in their entirety by reference to the Syndicated Credit Agreement and the 18-Month Credit Agreement, which are incorporated by reference as Exhibits 10-a and 10-b to this Current Report on Form 8-K and are incorporated herein by reference.

The Syndicated Credit Agreement

Subject to customary conditions, the obligations of the lenders under the Syndicated Credit Agreement to provide advances extend from the effective date of the agreement to a termination date of March 21, 2015, unless prior to that date either: (i) AT&T reduces to $0 the commitments of the lenders under the Syndicated Credit Agreement or (ii) certain events of default occur.

Advances would bear interest, at AT&T’s option, either:

The Applicable Margin for a Eurodollar Rate Advance under the Tranche A Facility will equal 1.000% if AT&T’s unsecured senior long-term debt is rated at least A- by Standard and Poor’s (“S&P”) or Fitch, Inc. (“Fitch”) or A3 by Moody’s Investors Service (“Moody’s”). The Applicable Margin for a Eurodollar Rate Advance under the Tranche A Facility will be 1.125% per annum if such ratings are BBB+ by S&P or Fitch or Baa1 by Moody’s and will be 1.250% per annum if such ratings are lower than BBB+ by S&P or Fitch or Baa1 by Moody’s. The Applicable Margin for a Base Rate Advance under the Tranche A Facility will be equal to the relevant Applicable Margin for a Eurodollar Rate Advance under the Tranche A Facility minus 1.00%.

The Applicable Margin for a Eurodollar Rate Advance under the Tranche B Facility will equal 1.125% if AT&T’s unsecured senior long-term debt is rated at least A- by S&P or Fitch or A3 by Moody’s. The Applicable Margin for a Eurodollar Rate Advance under the Tranche B Facility will be 1.250% per annum if such ratings are BBB+ by S&P or Fitch or Baa1 by Moody’s and will be 1.375% per annum if such ratings are lower than BBB+ by S&P or Fitch or Baa1 by Moody’s. The Applicable Margin for a Base Rate Advance under the Tranche B Facility will be equal to the relevant Applicable Margin for a Eurodollar Rate Advance under the Tranche B Facility minus 1.00%.

In the event that AT&T’s unsecured senior long-term debt ratings are split by S&P, Moody’s and Fitch, then the Applicable Margin will be determined by the highest rating, unless the lowest of such ratings is more than one level below the highest of such ratings, in which case the pricing will be the rating that is one level above the lowest of such ratings.

As of the date of this filing, AT&T’s unsecured senior long-term debt is rated A- (Negative Outlook) by S&P, A3 (Review for Downgrade) by Moody’s and A by Fitch (Rating Watch Negative). S&P, Moody’s and Fitch may change their ratings at any time and AT&T disclaims any obligation to provide notice of any changes to these ratings.

Advances under the Syndicated Credit Agreement after the effective date thereof are not conditioned on the absence of a material adverse change.

The Syndicated Credit Agreement contains customary affirmative and negative covenants, as well as a debt-to-EBITDA financial ratio covenant that AT&T will maintain, as of the last day of each fiscal quarter, a ratio of not more than 3.0 to 1 of:

(A) all items that would be treated under accounting principles generally accepted in the United States (GAAP) as specified in the Syndicated Credit Agreement as indebtedness on AT&T’s consolidated balance sheet, to

(B) the net income of AT&T and its consolidated subsidiaries, determined on a consolidated basis for the four quarters then ended in accordance with GAAP, adjusted to exclude the effects of (a) gains or losses from discontinued operations, (b) any extraordinary or other non-recurring non-cash gains or losses (including non-cash restructuring charges), (c) accounting changes including any changes to Accounting Standards Codification 715 (or any subsequently adopted standards relating to pension and postretirement benefits) adopted by the Financial Accounting Standards Board after the date of the Syndicated Credit Agreement, (d) interest expense, (e) income tax expense or benefit, (f) depreciation, amortization and other non-cash charges (including actuarial gains or losses from pension and postretirement plans), (g) interest income, (h) equity income and losses and (i) other non-operating income or expense. In the event AT&T makes a material acquisition or a material disposition (each as defined in the Syndicated Credit Agreement) during the relevant four quarter period, pro forma effect is given to such material acquisition or material disposition, as if such material acquisition or material disposition occurred on the first day of such period.

Events of default under the Syndicated Credit Agreement, which would result in the acceleration or permit the lenders to accelerate, as applicable, required payment and which would increase the Applicable Margin by 2.00% per annum, whether automatically or upon the request of the requisite lenders, as applicable, include the following:

“Existing Credit Agreement” means the $5,000,000,000 Amended and Restated Credit Agreement dated as of December 11, 2013, among AT&T, the lenders parties thereto and Citibank, N.A., as administrative agent (as such credit agreement may be amended from time to time), or any credit agreement refinancing thereof. The Existing Credit Agreement was filed as Exhibit 10.1 to Form 8-K of AT&T Inc. (File Number 1-8610) which was filed with the U.S. Securities and Exchange Commission on December 11, 2013.

The 18-Month Credit Agreement

Subject to customary conditions, the obligations of the lender under the 18-Month Credit Agreement to provide advances extend from the effective date of the agreement to a termination date of March 21, 2015, unless prior to that date either: (i) AT&T reduces to $0 the commitment of the lender under the 18-Month Credit Agreement or (ii) certain events of default occur.

Advances would bear interest, at AT&T’s option, either:

The Applicable Margin for a Eurodollar Rate Advance under the 18-Month Credit Agreement will equal 0.800% if AT&T’s unsecured senior long-term debt is rated at least A- by S&P or Fitch or A3 by Moody’s. The Applicable Margin for a Eurodollar Rate Advance under the 18-Month Credit Agreement will be 0.900% per annum if such ratings are BBB+ by S&P or Fitch or Baa1 by Moody’s and will be 1.000% per annum if such ratings are lower than BBB+ by S&P and Fitch or Baa1 by Moody’s. The Applicable Margin for a Base Rate Advance under the 18-Month Credit Agreement will be 0%.

In the event that AT&T’s unsecured senior long-term debt ratings are split by S&P, Moody’s and Fitch, then the Applicable Margin will be determined by the highest rating, unless the lowest of such ratings is more than one level below the highest of such ratings, in which case the pricing will be the rating that is one level above the lowest of such ratings.

Advances under the 18-Month Credit Agreement after the effective date thereof are not conditioned on the absence of a material adverse change.

The 18-Month Credit Agreement contains affirmative and negative covenants and events of default equivalent to those contained in the Syndicated Credit Agreement.

Item 9.01 Financial Statements and Exhibits.

The following exhibits are filed as part of this report:

(d) Exhibits

Signature

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.