Exhibit 5.1


                                February 12, 2001

SLM Holding Corporation
11600 Sallie Mae Drive
Reston, Virginia 20193

Ladies and Gentlemen:

         I am Senior Vice President and General Counsel of SLM Holding
Corporation (the "Corporation") and, as such, I have acted as counsel for the
Corporation in the preparation of a Registration Statement on Form S-3 (File No.
333-54642) (the "Registration Statement") filed with the Securities and Exchange
Commission under the Securities Act of 1933, as amended (the "Securities Act")
in connection with the proposed offer and sale up to 7,909,505 shares of common
stock, par value .20 per share (the "Common Stock"), of the Corporation. Such
shares are to be sold by the selling shareholders in the named Registration
Statement.

         I have examined or am otherwise familiar with the Certificate of
Incorporation, the By-Laws of the Corporation, as amended, the Registration
Statement, such of the Corporate Proceedings as have occurred as of the date
hereof, and such other documents, records, and instruments as I have deemed
necessary or appropriate of the purposes of this opinion.

         Based on the foregoing, I am of the opinion that the Common Stock is
duly and validly authorized and issued, fully paid, and nonassessable.

         I have also assumed (a) the accuracy and truthfulness of all public
records of the Corporation and of all certifications, documents and other
proceedings examined by me that have been produced by officials of the
Corporation acting within the scope of their official capacities, without
verifying the accuracy or truthfulness of such representations, and (b) the
genuineness of such signatures appearing upon such public records,
certifications, documents and proceedings. I express no opinion as to the laws
of any jurisdiction other than the laws of the District of Columbia, the General
Corporation Law of the State of Delaware, and the federal laws of the United
States of America.

         I hereby consent to the filing of this opinion as an exhibit to the
Registration Statement and to being named in the Prospectus included therein
under the caption "Legal Matters" with respect to the matters stated therein
without implying or admitting that I am an "expert" within the meaning of the
Securities Act, or other rules and regulations of the Securities and Exchange
Commission issued thereunder with respect to any part of the Registration
Statement, including this exhibit.

                                                     Very truly yours,

                                                     /s/ MARIANNE M. KELER

                                                     Marianne M. Keler