
<PAGE>
 
                                                                       Exhibit 5



                 [LETTERHEAD OF VINSON & ELKINS APPEARS HERE]

                                August 2, 1994

Halliburton Company
3600 Lincoln Plaza
500 North Akard
Dallas, Texas 75201

Gentlemen:

     We have acted as counsel for Halliburton Company (the "Company") for a 
number of years and are familiar with the Halliburton Company 1993 Stock and 
Long-Term Incentive Plan (the "Plan"), pursuant to which shares of Common Stock,
$2.50 par value ("Common Stock"), of the Company will be issued to certain key 
employees of the Company and its subsidiaries. We have assisted in the 
preparation of the Plan and the Registration Statement on Form S-8, under the 
Securities Act of 1933, as amended, to be filed on August 2, 1994 with the 
Securities and Exchange Commission by the Company with respect to the shares of 
Common Stock and Preferred Stock Purchase Rights of the Company to be issued 
under the Plan.

     In this connection, we have examined such certificates, documents and 
records as we have deemed relevant and necessary as a basis of our opinions 
hereinafter set forth, including, among other things, the Plan and copies of 
relevant resolutions passed by the Board of Directors and Stockholders of the 
Company. The Plan provides that shares of Common Stock to be issued thereunder 
may be authorized but unissued Common Stock or Common Stock previously issued 
and outstanding and reacquired by the Company. The opinion hereinafter set forth
relates to securities originally issued under the Plan.

     Based upon the foregoing, we are of the opinion that:

     (i)    The shares of Common Stock to be issued pursuant to various awards
            under the Plan have been duly authorized and, when (a) the
            Registration Statement has become effective under the Securities Act
            of 1933, as amended, and the pertinent provisions of any state
            securities laws, as may be applicable, have been complied with and
            (b) the shares of Common Stock are issued and paid for in accordance
            with the terms of the Plan and any stock option, restricted
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Halliburton Company
August 3, 1994
Page 2


           stock or other agreement pursuant to which such shares would be 
           issuable under the Plan, such shares of Common Stock shall be validly
           issued, fully paid and non-assessable and any related Preferred 
           Stock Purchase Rights shall be validly issued.


     (ii)  The Plan is not subject to the requirements of the Employee 
           Retirement Income Security Act of 1974, as amended.

     This opinion is rendered as of the effective date of the Company's 
Registration Statement. We hereby consent to the statements with respect to us
under Item 5 of the Registration Statement and to the filing of this opinion as 
an exhibit to the Registration Statement, but we do not admit that we are within
the class of persons whose consent is required under Section 7 of the Securities
Act of 1933 or the rules and regulations of the Securities and Exchange 
Commission thereunder. 
 
                                                      Very truly yours,
                                
                                                      /s/ Vinson & Elkins L.L.P.
                                                      VINSON & ELKINS L.L.P.
     


