A system for securing a valve actuator to body of a valve assembly includes an actuator housing having housing lugs protruding radially to define a plurality of housing slots therebetween. A bonnet has bonnet lugs protruding radially to define a plurality of bonnet slots therebetween. Each of the housing lugs are sized to pass axially through a respective one of the bonnet slots when the actuator housing is in a released position and, after passing through the bonnet slots, the actuator housing is rotatable to a locked position where at least a portion of one or more of the housing lugs is axially aligned with a portion of a respective bonnet lug to prevent axial movement of the actuator housing, the actuator housing rotating less than one full revolution between the released and locked positions. A securing mechanism prevents relative rotation between the actuator housing and the bonnet.