Adjustable reverse shoulder prostheses are disclosed herein. A glenoid assembly includes a glenoid plate configured for fixation to a glenoid bone for a reverse shoulder prosthesis; a glenosphere configured for connection to the glenoid plate; and an adjustment plate, wherein the adjustment plate has a connection for directly engaging the glenosphere, and wherein the adjustment plate has an articulation for directly engaging the glenoid plate at a variable angular orientation. During a reverse total shoulder arthroplasty method, a glenoid plate is fixated to a glenoid bone; an adjustment plate, configured for interfacing with both the glenoid plate and a glenosphere, is locked to the glenoid plate, wherein the adjustment plate is configured for angular orientation or positional change relative to the glenoid plate; a glenosphere is connected to the adjustment plate; and an angular orientation and position of the glenosphere relative to the fixated glenoid plate is independently adjusted.