Elsa Lopez McGuire, 79, a former embassy social secretary, translator and Spanish teacher, died of a lung ailment wednesday at her home in Washington.

During her 46 years here, Mrs. McGuire had worked with the embassies of The Dominican Republic and Nicaragua. She was a secretary-translator with the Export-Import Bank and the State Department.

She taught at Georgetown Niversity and also gave private Spanish lessons to a number of Washington residents. They ranged from young children in her neighborhood to such notables as Mrs. Lyndon B. Johnson, when the latter's husband was in the White House.

Mrs. McGuire was born in Guatemala. She came to the United States with her family in 1920 when her father, Ignzio Lopez Andrade, was ousted as vice president of Guatemala in a political coup.

She attended Southern Methodist University in Texas before her marriage in 1931 to Erskine E. McGuire, a businessman. They came to Washington in 1934. Mr. McGuire was drowned later that year at a Chesapeake Bay beach, when he attempted to rescue a companion.

Mrs. McGuire is survived by a brother, Luis Felipe, and a sister, Guillermina Lopez, both of Guatemala, and another sister, Aida Lopez de Ynestroza of Tegucigalpa, Honduras.