This letter examines the dependence of the natural frequency in a microelectromechanical resonator on externally applied acceleration. The particular structure studied is an electrostatically coupled, single anchored, double-ended silicon tuning fork. The authrors find that the acceleration dependence in this resonator is primarily due to axial stress on the resonator beams. Measurements show an acceleration sensitivity Δf f0 of 7× 10-9 g, which is comparable to values found for typical quartz crystal resonators. This result was obtained using dynamic (vibration) measurements, and validated using theoretical analysis and finite element simulations.