Control apparatus for hybrid vehicle drive system including: first differential mechanism provided with a rotary element connected to engine and rotary element connected to a first electric motor; a second differential mechanism provided with a rotary element connected to second electric motor and a rotary element connected to output rotary member; first clutch configured to selectively connect rotary element of first differential mechanism connected to engine or first electric motor, to rotary element of second differential mechanism connected to output rotary member; manually operated shifting device; and parking lock mechanism provided with parking lock gear fixed directly or indirectly to output rotary member and rotary motion which is prevented when shifting device is placed in parking position, control apparatus including parking lock control portion configured to release parking lock gear for permitting rotary motion of parking lock gear while first clutch is placed in its engaged state.