A rigid-inflatable boat (RIB) or rigid-hulled inflatable boat, (RHIB) is a light-weight but high performance and high capacity boat constructed with a solid, shaped hull and flexible tubes at the gunwale. The design is stable and seaworthy. The inflatable collar allows the vessel to maintain buoyancy if a large quantity of water is shipped aboard. The RIB is a development of the inflatable boat.

Zodiac is a tradename for a make of inflatable boat, but often has become a genericized tradename used to mean any inflatable boat or RIB.

RIBs are commonly 4 to 9 meters (13 to 28 ft) long, although they can range in length between 2.5 and 18 meters (7.5 and 55 ft). A RIB is often propelled by one or more outboard motors or an inboard motor turning water jet or stern drive. Generally the power of the motors is in the range of 5 to 300 horse power (4 to 220 kW). In some cases multiple engines can be installed either as outboards or as inboard engines.

RIBs are used as rescue craft, safety boats for sailing, dive boats or tenders for larger boats and ships. Their shallow draught, high maneuverability, speed and relative immunity to damage in low speed collisions are advantages in these applications.

RIBs up to about 7 metres in length can be towed on trailers on the road, making them attractive as leisure craft.