Abstract: EXAFS spectroscopy has been used to monitor changes in divalent cation site geometries across the P2/c−P1¯ phase transition in the sanmartinite (ZnWO₄)-cuproscheelite (CuWO₄) solid solution at ambient and liquid nitrogen temperatures. In the ZnWO₄ end member, Zn occupies axially-compressed ZnO₆ octahedra with two axial Zn-O bonds at approximately 1.95 Å and four square planar Zn-O bonds at approximately 2.11 Å. The substitution of Zn by Cu generates a second Zn environment with four short square planar Zn-O bonds and two longer axial Zn-O bonds. The proportion of the latter site increases progressively as the Cu content increases. Cu EXAFS reveals that the CuO₆ octahedra maintain their Jahn-Teller axially-elongate geometry throughout the majority of the solid solution and only occur as axially-compressed octahedra well within the stability field of the Zn-rich phase with monoclinic long-range order.