A grommet configured to seal an insertion hole formed in a panel into which a pipe is inserted may include a base that is configured to be connected to the insertion hole, a boot that is integrally formed in the base and has a thinned wall thickness, and at least one rib that is formed in the boot. The boot has a truncated cone-shaped main portion having an insertion bore into which the pipe can be inserted, and a connecting portion that is folded back from a circumferential periphery of the main portion via a folded back portion and is connected to the base. The at least one rib is formed in the main portion and the connecting portion while straddling the folded back portion, so as to restrict the main portion from being axially displaced relative to the base.