EXHIBIT 5.1 Alston & Bird LLP One Atlantic Center 1201 West Peachtree Street Atlanta, Georgia 30309-3424 404-881-7000 Fax: 404-881-7777 Telex: 54-2996 June 19, 1998 LHS Group Inc. Six Concourse Parkway Suite 2700 Atlanta, Georgia 30328 Re: Form S-8 Registration Statement -- LHS Group Inc. 1998 Employee Stock Purchase Plan and LHS Group Inc. Amended and Restated Stock Incentive Plan Ladies and Gentlemen: We have acted as counsel for LHS Group Inc., a Delaware corporation (the "Corporation"), in connection with the referenced Registration Statement on Form S-8 (the "Registration Statement") being filed by the Corporation with the Securities and Exchange Commission (the "Commission") under the Securities Act of 1933, as amended, and covering 8,500,000 shares of the Corporation's common stock, $0.01 par value ("Common Stock"), that may be issued pursuant to (i) the LHS Group Inc. 1998 Employee Stock Purchase Plan and (ii) the LHS Group Inc. Amended and Restated Stock Incentive Plan (collectively, the "Plans"). This Opinion Letter is rendered pursuant to Item 8 of Form S-8 and Item 601(b)(5) of Regulation S-K. In the capacity described above, we have considered such matters of law and of fact, including the examination of originals or copies, certified or otherwise identified to our satisfaction, of such records and documents of the Corporation, certificates of public officials and such other documents as we have deemed appropriate as a basis for the opinions hereinafter set forth. The opinions set forth herein are limited to the laws of the State of Delaware. Based upon the foregoing, it is our opinion that the 8,500,000 shares of Common Stock covered by the Registration Statement and to be issued pursuant to the Plans, when issued in accordance with the terms and conditions of the Plans, will be legally and validly issued, fully paid and nonassessable. The Opinion expressed herein is limited to the laws of the State of Delaware as codified in the General Corporation Law of the State of Delaware. This Opinion Letter is provided to you for your benefit and for the benefit of the Commission, in each case, solely with regard to the Registration Statement, may be relied upon by you and the Commission only in connection with the Registration Statement, and may not be relied upon by any other person or for any other purpose without our prior written consent. We hereby consent to the filing of this opinion as an exhibit to the Registration Statement and further consent to the use of our name wherever appearing in the Registration Statement. Sincerely, ALSTON & BIRD LLP By: /s/ Laura G. Thatcher --------------------- Partner -2-