The 1978 GP Ouest-France was the 42nd edition of the GP Ouest-France cycle race and was held on 22 August 1978. The race started and finished in Plouay. The race was won by Pierre-Raymond Villemiane.
General classification
Final general classification Rank Rider Time 1 2 + 0" 3 + 25" 4 + 25" 5 + 25" 6 + 54" 7 + 3' 34" 8 + 3' 34" 9 + 3' 34" 10 + 3' 34"
References