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                                                                     EXHIBIT 5.1

                          WALLER LANSDEN DORTCH & DAVIS
                    A PROFESSIONAL LIMITED LIABILITY COMPANY
                              NASHVILLE CITY CENTER
                          511 UNION STREET, SUITE 2100
                             POST OFFICE BOX 198966
                         NASHVILLE, TENNESSEE 37219-8966
                                 (615) 244-6380

                                January 14, 1998

Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, DC 20549

         RE:      Radio Systems Corporation
                  Registration Statement on Form S-1
                  Registration No. 333-40593

Ladies and Gentlemen:

         We are acting as counsel to Radio Systems Corporation, a Tennessee
corporation (the "Company"), in connection with the registration under the
Securities Act of 1933 (the "Act") of an aggregate of 2,167,750 shares of the
Company's Common Stock, no par value per share (the "Shares"), pursuant to a
Registration Statement on Form S-1 (the "Registration Statement"). We have
examined and relied upon such records, documents and other instruments as in our
judgment are necessary and appropriate in order to express the opinion
hereinafter set forth, and have assumed the genuineness of all signatures, the
authenticity of all documents submitted to us as originals, and the conformity
to original documents of all documents submitted to us as certified or
photostatic copies.

         Based upon the foregoing, we are of the opinion that the Shares being
sold by the Company will be, when issued and delivered in the manner and on the
terms described in the Registration Statement (after the Registration Statement
is declared effective), duly authorized, validly issued, fully paid and
non-assessable.

         We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and further consent to the reference to us under the
caption "Legal Matters" in the prospectus included in the Registration
Statement.

                                        Very truly yours,

                                        /s/ Waller Lansden Dortch & Davis, PLLC