Abstract: A deflector for attaching to forward portions of an open frame boat trailer to deflect road debris thrown rearwardly from the wheels of a vehicle towing the trailer comprises a generally trapezoidally-shaped deflecting member, major portions of which are flat. A forward edge portion of the member, which forms the shorter of the parallel sides of the trapezoid, is inclined upwardly and forwardly; whereas, an opposite rearward edge portion is inclined downwardly and rearwardly. Swept back side edges are inclined upwardly and generally outwardly and forwardly. The flat portion of the member rests upon, and is attached to, generally longitudinal beams of the trailer. The deflector is positioned rearwardly of the trailer hitching portion and extends rearwardly to beneath upswept bow portions of a boat carried on the trailer. The inclined edge portions of the deflector increase deflection efficiency while minimizing deflector size, and also add rigidity to the deflector.