An adjustment turret for an optical sight includes a body, an adjustment shaft, a cap, and a locking pin. The body includes a cavity and an axial bore. The adjustment shaft threadably engages the axial bore for relative rotation therebetween. The cap is connected to the adjustment shaft for rotation with the adjustment shaft relative to the body and is axially movable relative to the body and the adjustment shaft between a first position and a second position. The locking pin is axially movable with the cap and is received in the cavity when the cap is in the first position to prevent relative rotation between the cap and the body and is removed from the cavity when the cap is in the second position to allow relative rotation between the cap and the body.