An analog T switch is disclosed which has high isolation in the off state. The analog T switch can include series-connected NMOS transistors having separate gate control. The gates of the NMOS transistors can be isolated from one another to improve off state isolation of the analog T switch. The analog switch can include series-connected PMOS transistors having separate gate control. The gates of the PMOS transistors can be isolated from one another to improve off state isolation of the analog T switch. The analog T switch can include a substrate voltage control circuit that controls the voltage of the substrate regions in which the PMOS transistors are formed. The substrate voltage control circuit can isolate the substrate regions of the PMOS transistors from one another in the off state to improve off state isolation of the analog T switch.