Combine oats, peanut butter, coconut, cocoa, and vanilla, mixing well; set aside.
Combine sugar, milk, and butter in a small saucepan; bring to a boil. Cook 1 minute, stirring constantly. Pour over reserved oat mixture; quickly stir to mix well.
Immediately drop by heaping teaspoonfuls onto waxed paper-lined baking sheets; let cool. Carefully remove from waxed paper to serve.