A bunkmate is someone who shares a bunk bed with you, usually in a cabin, dormitory, or other place where people sleep in rooms with multiple beds stacked on top of each other. At summer camp, your bunkmate might sleep on the bed above or below yours. On a school trip, you and your bunkmate might take turns choosing who gets the top bunk.

The word can also refer more broadly to anyone sharing your sleeping quarters, even if you're not in actual bunk beds. Roommates at boarding school or camp are often called bunkmates because they share the same space and experience many of the same daily routines together.

Bunkmates are around each other during personal moments: getting ready for bed, waking up, storing belongings, and sharing tight spaces. A considerate bunkmate respects privacy, keeps their area reasonably tidy, and tries not to wake others up unnecessarily. Some of the strongest friendships form between bunkmates who start out as strangers but discover they can work well together in close quarters.