Palatinate-Simmern (German: Pfalz-Simmern) was one of the collateral lines of the Palatinate line of the House of Wittelsbach.
The Palatinate line of the House of Wittelsbach was divided into four lines after the death of Rupert III in 1410, including the line of Palatinate-Simmern with its capital in Simmern. This line became extinct in 1685 with the death of Charles II. The Palatinate-Neuburg line inherited the estate.