The 1977 Yugoslavian motorcycle Grand Prix was the seventh round of the 1977 Grand Prix motorcycle racing season. It took place on 19 June 1977 at the Circuit d'Opatija. The event was marred by 2 fatalities, and this turned out to be the last Yugoslavian motorcycle Grand Prix at Opatija. The event moved to the further inland Rijeka circuit.
This event took place under heavy rumors of it being cancelled because the safety conditions of the seaside Opatija circuit. The FIM, the governing body of motorcycle racing had issued an ultimatum to the organizers that if they did not improve safety at the circuit, the event would be cancelled. The circuit was very narrow, very fast and had numerous roadside obstacles including light posts, houses, solid rock walls and trees. The Grand Prix had already been boycotted by 500cc riders in 1973 and a rider had been killed in 1974. The event went ahead anyway.
The Grand Prix weekend turned out to be a disaster. In one of the worst days in motorcycle racing history, during practice for the 250 cc race, Giovanni Ziggiotto crashed when his motorcycle's engine seized. He was hit by another rider and died four days later in hospital. During the 50 cc race, Ulrich Graf crashed when his bike developed a rear tyre puncture. He suffered serious head injuries and died later in hospital.