We describe a Riemann-Hilbert problem for a family of q-orthogonal polynomials, {Pn(x)} ∞ n=0 , and use it to deduce their asymptotic behaviours in the limit as the degree, n, approaches infinity. We find that the q-orthogonal polynomials studied in this paper share certain universal behaviours in the limit n → ∞. In particular, we observe that the asymptotic behaviour near the location of their smallest zeros, x ∼ q n/2 , and norm, Pn 2 , are independent of the weight function as n → ∞.