The XI Constitutional Government of Portugal (Portuguese: XI Governo Constitucional de Portugal) was the 11th government of the Third Portuguese Republic, in office from 17 August 1987 to 31 October 1991.

It was formed by members of the Social Democratic Party (PSD) and had Aníbal Cavaco Silva, leader of the PSD, as Prime Minister.

It was the first single-party government with an absolute majority in the Assembly of the Republic since the Carnation Revolution.

On 5 January 1990, the position of Vice Prime Minister was extinguished and the Ministry of Environment and Natural Resources was created, making a total of 17 ministries.

The government also included the Ministers of the Republic for the Autonomous Regions of Azores and Madeira.