We present generalized theoretical analysis and experimental realization of active quality factor control for the self-oscillating quartz tuning-fork (QTF). The quality factor Q and resonance frequency can be controlled by adding a phase shifted signal of proper gain with respect to the QTF motion. It is demonstrated that the analysis of QTF can be extended to other quartz resonators which are analyzed by an equivalent circuit-a combination of a parallel circuit of an harmonic L-R-C and a stray capacitance C0
. Finally, we suggest the prospect of several applications by using the active Q control of QTF such as increasing force sensitivity, reducing scanning time in scanning probe microscopy, and feedback cooling of electromechanical resonator.