An ergonomic chair with an auto-adjusting headrest having a base assembly including floor base, a seat bottom, and vertical structure. A seat back frame and back plate are pivotally attached to the base assembly. An arc-shaped guide bar and head rest restraint are slideably disposed on the back plate. such that the back plate slides approximately parallel to the seat back frame. Arc shaped guide bar rotates as the seat back is tilted rearward and forward.