This paper introduces a rigorous derivation of the quasi-hydrostatic quasi-geostrophic (QHQG) equations of large scale ocean as the Rossby number goes to zero. We follow classical techniques for the derivation of the quasi-geostrophic (QG) equations (as in [BB94]), but the primitive equations that we consider account for the nontraditional rotating terms, as in [LPR10]. We end up with a slightly different QG model with a tilted vertical direction, which has been illustrated in previous works using the primitive equations (see [PMHA97, She04, WB06, GZMvH08, SKR02]), and for which we prove local and global existence results.