The main cause of the French and Indian war was the French didn’t like how Britain was treating them so they rebelled and then their was a war, but the Indians sided with the French they didn’t fight against each other. The Indians sided with both Britain and the French but the main cause was because THE FRENCH DIDNT LIKE HOW THE KING OF BRITAIN( King George) WAS TREATING THEM SO THEY REBELLED AND THAT STARTED THE WAR!... I hope this answer helps