Margarita Gómez-Acebo y Cejuela was born on 6 January 1935 in Villa Alba, Collado Villalba, Madrid, during the Second Spanish Republic,[2] as the second child and only daughter of the two children of Spanish nobles: Manuel Gómez-Acebo y Modet, 4th Marquess of Cortina, a state counsellor and lawyer of commercial and banking companies (eldest child of José Gómez Acebo y Cortina, 3rd Marquess of Cortina and wife Margarita Marta Modet y Almagro) and wife María de las Mercedes Cejuela y Fernández (daughter of Manuel Cejuela y González-Orduña and wife María de las Mercedes Fernández Molano).

[2] In recognition of their parents' murders, Margarita and her elder brother José-Luis (1930–2010) both received the Suffering for the Motherland Medal from Francoist Spain.

After the death of their parents, Margarita and José-Luis continued to live at Villa Alba for some time until they were taken in by their father's close friend, the marquess of Casa Pissaro[2] until May 1937, when the siblings were to go to northern Spain, but due to the war were instead forced to follow a route via Valencia to Barcelona and then to France to stay with their paternal grandmother, Doña Margarita Marta Modet y Almagro, until her death in 1940.

[2] They were then taken in by their paternal uncle, Don Juan Gómez-Acebo y Modet, Marquess of Zurgena, and his family until his death,[2] when they moved in with their other paternal uncle, Don Jaime Gómez-Acebo y Modet, and his wife, Doña Isabel Duque de Estrada y Vereterra, 9th Marchioness of Deleitosa,[2] as well as their children, including Don Luis Gómez-Acebo (later husband of Infanta Pilar of Spain, Duchess of Badajoz, eldest sister of King Juan Carlos I of Spain and aunt of King Felipe VI of Spain.

The legality of this transaction is disputed by Bulgarian politicians in spite of the settled approval sentenced by the Constitutional Court.