A surgical instrument comprising: an elongate shaft defining a longitudinal axis; an end effector coupled to said elongate shaft for selective pivotal travel relative to said elongate shaft, said end effector having at least one movable portion responsive to opening and closing motions; a closure member interfacing with said at least one movable portion of said end effector to selectively apply said closing motion thereto; an articulation control system operably interfacing with said end effector to apply articulation motions thereto; and an articulation lock system interfacing with said articulation control system and said closure member, said articulation lock system configured to move from an unlocked position wherein said articulation control system applies said articulation motions to said end effector and a locked position wherein said articulation lock system prevents said articulation control system from applying said articulation motions to said end effector upon application of said closure motion by said closure member, wherein the articulation control system comprises a nozzle supported relative to said elongate shaft such that said nozzle may be axially moved in first and second axial directions relative to said elongate shaft and rotation of said nozzle about said longitudinal axis causes said end effector to rotate about said longitudinal axis, and wherein said articulation control system comprises an articulation assembly operably interfacing with said end effector and said nozzle such that movement of said nozzle in said first axial direction causes said articulation assembly to apply a first articulation motion to said end effector and movement of said nozzle in said second axial direction causes said articulation assembly to apply a second articulation motion to said end effector. an elongate shaft defining a longitudinal axis; an end effector coupled to said elongate shaft for selective pivotal travel relative to said elongate shaft, said end effector having at least one movable portion responsive to opening and closing motions; a closure member interfacing with said at least one movable portion of said end effector to selectively apply said closing motion thereto; an articulation control system operably interfacing with said end effector to apply articulation motions thereto; and an articulation lock system interfacing with said articulation control system and said closure member, said articulation lock system configured to move from an unlocked position wherein said articulation control system applies said articulation motions to said end effector and a locked position wherein said articulation lock system prevents said articulation control system from applying said articulation motions to said end effector upon application of said closure motion by said closure member, wherein the articulation control system comprises a nozzle supported relative to said elongate shaft such that said nozzle may be axially moved in first and second axial directions relative to said elongate shaft and rotation of said nozzle about said longitudinal axis causes said end effector to rotate about said longitudinal axis, and wherein said articulation control system comprises an articulation assembly operably interfacing with said end effector and said nozzle such that movement of said nozzle in said first axial direction causes said articulation assembly to apply a first articulation motion to said end effector and movement of said nozzle in said second axial direction causes said articulation assembly to apply a second articulation motion to said end effector.