Gregorio Peces-Barba (13 January 1938 – 24 July 2012) was a Spanish politician and jurist.
He was one of the seven jurists who wrote the Spanish Constitution of 1978 as a representative of the Spanish Socialist Workers' Party.
Peces-Barba was born in Madrid.
He studied Law in Madrid and Strasbourg, writing his thesis about Jacques Maritain.
He was a member of the Socialist Party since 1972 and was chosen as congressman for the province of Valladolid in 1977 in the first democratic elections in Spain in forty years.
He was one of the seven jurists who wrote the constitution approved in referendum in 1978, and so he is consider a father of the constitution.
In 1982 he was elected president of the congress of deputies and held that chair until 1986 when he decided not to rerun.