The 1985 Portuguese Grand Prix was a Formula One motor race held in Estoril on 21 April 1985.

On lap 4, Riccardo Patrese made contact with Stefan Johansson while attempting to pass him on the inside line.

Soon after, Stefan Bellof and Manfred Winkelhock made contact on track; both were able to restart their cars and rejoin the race.

The top four held steady to lap 15, with Niki Lauda and Patrick Tambay in 5th and 6th, 25 seconds behind 4th place Alboreto.

At 20 laps, Senna had extended his lead on his teammate de Angelis to 30 seconds, with Prost and Alboreto still close behind.

Near lap 30, Mauro Baldi spun out and ended on track with damage to his car and leaving a lot of mud on the racing surface, and Alain Prost retired with damage after spinning and striking the rear of his car on the track barrier.

The race was not stopped or interrupted, but did continue at an unusually slow pace because of the poor weather conditions.