<p>Due to its potential applications in quantum mechanics, the study of theory in quaternionic Hilbert (Q-Hilbert) spaces has interested some researchers. This paper addresses approximate oblique dual (A-O-D) frames in separable Q-Hilbert spaces. We present several sufficient conditions for constructing A-O-D frames. As an application, we present an example to construct A-O-D frames. We obtain a distinct expression for all A-O-D frames of any given frame. We also study perturbation-stability of A-O-D frames by two different perturbation methods.</p>