An investigation on the damping effects of different gas mediums in a capacitive MEMS accelerometer is carried out. Air, argon, carbon-dioxide, helium, hydrogen, nitrogen and oxygen are considered for the study. Detailed calculations of the temperature and pressure effects on the properties of various gases are first performed. An electrical equivalent circuit is developed for the accelerometer structure incorporating squeezed film effects. The equivalent circuit is used to determine the dynamic and frequency response of the accelerometer under different pressures at 300 K, for various gases. From the simulation, the system bandwidth, resonant frequency, rise time and settling time are evaluated. Further, for the structure under investigation, the static sensitivity of the displacement and capacitance were obtained as 17 nm g−1 and 101 fF g−1, which is constant for all gases. It is inferred that helium provides better damping at low pressures, compared to other gases. However, at higher pressures, all the gases are found to behave similarly.