Who was involved in the anti-war movement?

Many people/groups were involved. Anti-war marches and other protests, such as the ones organized by Students for a Democratic Society (SDS), attracted a widening base of support over the next three years, peaking in early 1968 after the successful Tet Offensive by North Vietnamesetroops proved that war's end was nowhere in sight. I mean, who wouldn't be mad? There was a draft that forced citizens to fight in a war they didn't even believe in! A war that lasted 19 YEARS and 180 days! 

Since there's too many people/groups to put here, go to this website and see the full list: https://en.wikipedia.org/wiki/List_of_anti-war_organizations

Hope this helps!!