What should I wear under a men's sweater? Shirts are definitely the best choice. Shirts with sweaters can make the overall shape more layered. Gentle and elegant shape, with a pair of pants, you can go out handsomely. This simple and casual combination can easily have a sense of fashion, and it is so easy to fall in love with fans! When a man wears a sweater with a shirt, he must pay attention to the fact that the sweater must fit to look good.