Roth was born in Buenos Aires, Argentina into a Jewish family. Cecilia Roth has made appearances in numerous television series. After working in Argentina in several films she moved to Spain, where she started a frequent collaboration with filmmaker Pedro Almodóvar. Roth went on to appear in six of his movies, either as lead, supporting actor or cameo.
She lived with Argentine musician Fito Páez for some years, with whom she adopted a child. Fito wrote the song "Cecilia" for her. The song is about their relationship and a passionate love letter to her. She is also the sister of another Argentine musician, Ariel Rot, member of the former Los Rodríguez band.