A ramp assembly for a pontoon boat includes a pair of ramp support members, at least one of a roller and a guide bar, and a ramp. The ramp support members are positioned beneath a deck of the pontoon boat and include a vertically-oriented portion. The at least one of the roller and the guide bar is mounted to the vertically-oriented portion of each ramp support member. The ramp includes a pair of side rails, each side rail positioned on a side of a ramp walkway, the side rails each having an upper rail member and a lower rail member joined by a web and forming an outboard pocket. The ramp is received between the ramp support members such that the at least one of the roller and the guide bar mounted to each vertically-oriented portion is positioned in the outboard pocket of each side rail.