A semiconductor device includes a fin protruding above a substrate; source/drain regions over the fin; nanosheets between the source/drain regions; and a gate structure over the fin and between the source/drain regions. The gate structure includes: a gate dielectric material around each of the nanosheets; a first liner material around the gate dielectric material; a work function material around the first liner material; a second liner material around the work function material; and a gate electrode material around at least portions of the second liner material.