Her father, Margarito Mendoza Aranal, Sr., was a sales manager, from Siasi, Sulu. Her mother, Soledad Lansigan Punzalan, was a public school teacher, from Bay, Laguna. She is married to Mario Jose E. Sereno, with whom she has two children.

Chief Justice Sereno’s paternal grandfather was surnamed Aranal y Dalaygon (or Dalaygon Aranal in Filipino, the son of Eleuterio Aranal and Francisca Dalaygon). Eleuterio was a native of Dauis, Bohol. Francisca was Moro, from Cantilan, Surigao (now Lanuza, Surigao del Sur).

Chief Justice Sereno’s paternal grandmother was named Dominga Mendoza. Dominga was born in Batangas.

Chief Justice Sereno’s maternal grandfather was Nicolás Punzalan y Galang (or Nicolás Galang Punzalan in Filipino, the son of Domingo Punzalan and Lutgarda Galang).

Chief Justice Sereno’s maternal grandmother was Simplicia “Plisa” Lansigan y Pantas (the daughter of Pedro Lansigan y Caldeo, or Pedro Caldeo Lansigan in Filipino, and of Francisca “Anda Iska” Pantas). Simplicia was born in Bay, Laguna. Pedro was the son of Juan Lansigan and Aquilina Caldeo.