Abstract: A gas lock breaker for oil well pumps includes a stationary barrel with a standing valve on the bottom, a reciprocating piston in the barrel with a traveling valve on the bottom of the piston, an unseating rod positioned above the standing valve and adapted to protrude into the traveling valve to unseat the ball closure thereof near the bottom extremity of the downstroke of the piston. For a conventional well of any normal depth equipped with a pump jack for piston displacement anywhere in the range of 1 to 5 meters (3.3 to 16.4 feet), the unseating rod protrudes through the traveling valve a distance of about 1 to 15 percent of the piston stroke, or about 5 to 13 cm. (2 to 5 in.). The standing valve cage is preferably 12 to 20 cm. (4.75 to 8.0 in.), and the traveling valve is set to approach within 15 to 30 cm. (6 to 12 in.) of the standing valve.