A putter comprising an adjustable hosel structure is disclosed herein. In particular, the putter comprises a hosel assembly comprising a shaft receiver and two interlocked bars that connect the shaft receiver to the putter head. A plurality of bolts connect the bars to the shaft receiver and the putter head, and these points of connection are joints about which the bars move, and which can be restrained to immobilize the hosel assembly or otherwise reversibly fix it in place so that a longitudinal shaft axis is aligned with a desired portion of the putter head. The hosel assembly preferably is adjustable along a horizontal, heel-to-toe axis, and is partially disposed, and secured, within a pocket on the heel side of the putter head.