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                                                                     EXHIBIT 5.1



                                KING & SPALDING
                          1185 Avenue of the Americas
                            New York, New York 10036



                                 June 20, 2001


Rock-Tenn Company
504 Thrasher Street
Norcross, Georgia 30071

         Re:      Registration Statement on Form S-3
                  of $300,000,000 of Debt Securities

Ladies and Gentlemen:

         We are counsel to Rock-Tenn Company, a Georgia corporation (the
"Company"), in connection with the preparation of a Registration Statement on
Form S-3 (the "Registration Statement") filed with the Securities and Exchange
Commission under the Securities Act of 1933, as amended, relating to
$300,000,000 aggregate principal amount of debt securities ("Debt Securities")
to be issued pursuant to that certain Indenture dated July 31, 1995 (the
"Indenture") between the Company and SunTrust Bank, a Georgia banking
corporation, as trustee (the "Trustee").

         In so acting, we have reviewed such matters of law and examined
original, certified, conformed or photographic copies of such other documents,
records, agreements and certificates as we have deemed necessary as a basis for
the opinions hereinafter expressed. In such review, we have assumed the
genuineness of signatures on all documents submitted to us as originals and the
conformity to original documents of all copies submitted to us as certified,
conformed or photographic copies, and, as to certificates of public officials,
we have assumed the same to have been properly given and to be accurate.

         For purposes of the opinions below, we have assumed that the execution
and delivery of, and the performance of all obligations under, the Indenture
have been duly authorized by all requisite action by the Trustee, and the
Indenture is a valid and binding agreement of the Trustee, enforceable against
the Trustee in accordance with its terms.

         This opinion is limited in all respects to the laws of the State of New
York, and no opinion is expressed with respect to the laws of any other
jurisdiction or any effect which such



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Rock-Tenn Company
June 20, 2001
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laws may have on the opinions expressed herein. This opinion is limited to the
matters stated herein, and no opinion is implied or may be inferred beyond the
matters expressly stated herein.

         Based upon the foregoing, and subject to all of the assumptions,
limitations and qualifications set forth herein, we are of the opinion that:

                  (i)      The Indenture has been duly authorized, executed
         and delivered by the Company and constitutes a valid and binding
         obligation of the Company enforceable against the Company in accordance
         with its terms subject, as to enforcement of remedies, to bankruptcy,
         insolvency, reorganization, moratorium or similar laws affecting
         creditors' rights generally, general equitable principles, and
         the discretion of courts in granting equitable remedies; and

                  (ii)     The Debt Securities, when the definitive terms and
         provisions thereof have been established in accordance with the
         Indenture and when executed and delivered by the Company and
         authenticated by the Trustee pursuant to the Indenture and delivered
         and paid for by the purchasers thereof, will constitute legal, valid
         and binding obligations of the Company, enforceable against the Company
         in accordance with their terms, subject, as to enforcement of remedies,
         to bankruptcy, insolvency, reorganization, moratorium or similar laws
         affecting creditors' rights generally, general equitable principles and
         the discretion of courts in granting equitable remedies.

         This opinion is given as of the date hereof, and we assume no
obligation to advise you after the date hereof of facts or circumstances that
come to our attention or changes in law that occur, which could affect the
opinions contained herein.

         We hereby consent to the filing of this opinion as an Exhibit to the
Registration Statement and to the reference to us under the caption "Validity of
Debt Securities" in the Prospectus that is included in the Registration
Statement.


                                               Very truly yours,


                                               /s/ King & Spalding