A whaleboat is a type of open boat that is relatively narrow and pointed at both ends, enabling it to move either forwards or backwards equally well. It was originally developed for whaling, and later became popular for work along beaches, since it does not to be turned around for beaching or refloating.

Whaleboats are traditionally oar-powered, although some might carry a small sail as backup. There is no rudder; steering is done with an oar held over the stern. Whaleboats used in whaling had a stout post mounted in the bow, around which the harpooneer would cinch the rope once the whale had been harpooned, and by which the whale would drag the boat until it was killed.

The term "whaleboat" may be used informally of larger whalers, or of a boat used for whale watching.

On modern warships, a relatively light and seaworthy boat for transport of ship's crew may be referred to as a whaleboat.