Single crystals of $ZnWO_4$ were grown successfully in the [100], [010] and [001] directions using the Czochralski method. The growth parameters and the formation of slip plane in $ZnWO_4$ crystals were studied. $ZnWO_4$ crystals had a cleavage plane of (010). The dislocation density on the (010) plane at the center of the crystal was lower than that of the edge region. It was inferred that the high density at the edge of the crystals was caused by the thermal gradient during crystal growth. The etch pit arrangement revealed the (100) slip plane to be most active during crystal growth.