Exhibit 8.1

December 6, 2006

SunTrust Banks, Inc.

303 Peachtree Street, NE

Atlanta, GA 30308

Ladies and Gentlemen:

We have acted as counsel to SunTrust Banks, Inc., a Georgia corporation (the “Company”), and SunTrust Capital VIII, a Delaware statutory trust (the “Trust”), in connection with the preparation and filing of a Registration Statement on Form S-3 and each post-effective amendment thereto (as amended, the “Registration Statement”), including the prospectus, dated October 18, 2006 (the “Prospectus”), as supplemented by the Prospectus Supplement, dated November 29, 2006 (the “Prospectus Supplement”), with the Securities and Exchange Commission pursuant to the Securities Act of 1933, as amended, relating to (A) $1,000,000,000 aggregate liquidation amount of 6.100% Trust Preferred Securities (the “Trust Preferred Securities”), (B) $10,000 aggregate liquidation amount of Trust common securities, (C) $1,000,010,000 principal amount of 6.100% Extendible Junior Subordinated Notes, and (D) a guarantee of payment on the Trust Preferred Securities to be provided by the Company.

In rendering the opinion set forth below, we have examined and relied upon such records, agreements, instruments and other documents as we have deemed relevant and necessary, including but not limited to, (i) the Registration Statement, including the Prospectus and the Prospectus Supplement, (ii) form of Second Amended and Restated Declaration of Trust, dated as of December 6, 2006, among the Company, U.S. Bank National Association, as property trustee, U.S. Bank Trust National Association, as Delaware trustee, the administrative trustees named therein, and the holders of the trust securities, (iii) Junior Subordinated Indenture, dated as of October 25, 2006, between the Company and U.S. Bank National Association, as trustee, and all supplements thereto, and (iv) form of Guarantee Agreement, dated as of December 6, 2006, between the Company and U.S. Bank National Association, as guarantee trustee. In connection with such examination, we have assumed the genuineness of all signatures, the legal capacity of natural persons, the authenticity of all documents submitted to us as originals, the conformity to the original documents of all documents submitted to us as duplicates or certified or conformed copies, and the authenticity of the originals of such latter documents.

SunTrust Banks, Inc.

December 6, 2006

Page 2

Our opinion set forth below is based on the Internal Revenue Code of 1986, as amended, Treasury Regulations promulgated thereunder, administrative pronouncements, and judicial precedents, all as of the date hereof. The foregoing authorities may be repealed, revoked or modified, and any such change may have retroactive effect.

Based on the foregoing, and subject to the qualifications, limitations and assumptions set forth in the Prospectus Supplement or stated herein, we are of the opinion that the statements set forth in the Prospectus Supplement under the caption “Certain United States Federal Income Tax Consequences,” to the extent such statements summarize U.S. federal income tax consequences of the purchase, beneficial ownership and disposition of the Trust Preferred Securities, are accurate in all material respects.

We express no opinion with respect to the transactions referred to herein or in the Prospectus Supplement other than as expressly set forth herein, nor do we express any opinion herein concerning any law other than the federal income tax law of the United States. Moreover, we note that our opinion is not binding on the Internal Revenue Service or courts, any of which could take a contrary position.

We hereby consent to the filing of this opinion letter as Exhibit 8.1 to the Registration Statement and to the use of our name under the caption “Certain United States Federal Income Tax Consequences” in the Prospectus Supplement.

Very truly yours,

/s/ King & Spalding LLP

KING & SPALDING LLP