Alexandre Tiedtke Quintanilha, GOSE (born 9 August 1945) is a Portuguese scientist, former director of the Instituto de Biologia Molecular e Celular (Institute of Molecular and Cell Biology) of the University of Porto and Professor at ICBAS - Abel Salazar Institute of Biomedical Sciences.

Alexandre Tiedtke Quintanilha, GOSE was born in Lourenço Marques (now Maputo) Portuguese East Africa on August 9, 1945, at the time a Portuguese colony.

His father, Aurélio Quintanilha, was Portuguese, from the Azores islands, and one of the first scientists to study fungi.

He worked for nearly 18 years at the University of California, Berkeley, in the US, before returning to Portugal in 1990 and becoming director of the Instituto de Biologia Molecular e Celular (Institute of Molecular and Cell Biology) of the University of Porto.

Alexandre is married to his longtime partner, North-American writer and journalist Richard Zimler.