In this work, we investigated the effects of polarizations and structural parameters on the optical absorption coefficient (OAC) and the intersubband transition between the three lowest energy levels E-1, E-2, and E-3 in the MgxZn(1 x)O/ZnO single quantum well. The energy of the electron in each level and its respective wavefunction are calculated by the numerical solution of Schrodinger and Poisson equations self-consistently using an effective mass approximation. Our findings exhibit that the intersubband transitions, Delta E-12 and Delta E-13, can be altered and controlled by varying the quantum well width and the magnesium composition, x. Moreover, our results suggest that the optical absorption coefficients, alpha(12) and alpha(13), can be modulated principally by adjusting the quantum well width, especially the optical absorption coefficient (alpha(12)), which presents a red shift by raising the quantum well thickness. Contrary to alpha(12), the optical absorption coefficient, alpha(13), can present either a red or a blue shift by increasing the quantum well width. The process responsible for this behavior, which can be suitable for optoelectronic device applications, is discussed here in detail. (C) 2018 Elsevier B.V. All rights reserved.