Abstract-This letter experimentally demonstrates 1.2 kV normally-off p-GaN gate lateral high-electronmobility transistors (HEMTs) on 200 mm diameter engineered substrates. The fabricated p-GaN gate HEMT with optimum gate-drain spacing exhibits a threshold voltage (Vth) of 3.2 V, an ON/OFF ratio of 108, low specific ON-resistance (Ron,sp) of $5.8 \mathrm{~m} \Omega-\mathrm{cm}^2$ and hard breakdown voltage (Vbd) at 1800 V. Optimized devices also show good wafer scale uniformity ( $\sigma_{\text {Ron }}=1.2 \%$ ) for the evaluated electrical parameters and passed on-wafer high temperature gate bias (HTGB) and reverse bias stress tests without device failures.