The fish family Bathymasteridae, commonly known as ronquils, is reviewed based on an examination of nearly 500 adult and larval specimens. An identification key based on adults is provided. Information on adult morphology, including a detailed description of the cephalic lateralis system for all members of the family, is included as well as information on the early life history stages of each genus. The family Bathymasteridae is distinguished within the suborder Zoarcoidei by the presence of ctenoid scales; well-developed pelvic bones and pelvic fins; numerous vomerine, palatine, and dentary teeth; and several internal osteological features. The Bathymasteridae includes seven species classified in the genera Ronquilus, Rathbunella, and Bathymaster, and is broadly distributed in the North Pacific, from Baja California to the Sea of Japan. The monotypic genus Ronquilus is found from southern California to the Gulf of Alaska. Rathbunella contains two species restricted to the coasts of California and Baja California. Bathymaster is the most diverse and broadly distributed genus, containing four species ranging from British Columbia around the Pacific Rim to the northern Sea of Japan.