Abstract. Orthogonal polynomials associated with Hq− semiclassical linear form will be studied as a generalization of the Hq−classical linear forms. The concept of class and a criterion for determining it will be given. The q-difference equation that the corresponding formal Stieltjes series satisfies is obtained. Also, the structure relation as well as the second order linear q-difference equation are obtained. Some examples of Hq−semiclassical of class 1 were highlighted.Introduction. The aim of this paper is to present the analysis and characterization of the q-analogues of D-semiclassical orthogonal polynomials. D-semiclassical orthogonal polynomials were introduced in a seminal paper by J. A. Shohat [22] and extensively studied by P. Maroni and coworkers in the last decade [13][14][15][16][17][18][19]. Furthermore, the present contribution is a natural continuation of a previous work [9] by me and P. Maroni on q-classical orthogonal polynomials.In the literature, the extension of classical orthogonal polynomials (Hermite, Laguerre, Jacobi, and Bessel) can be done in the q-case from three basic approaches (see [2] for a comparative analysis).The first one is related with the so called Askey Tableau, where all the classical families appear in a limiting process from the top of Askey-Wilson polynomials (see [10]).The second one concerns the hypergeometric character of classical orthogonal polynomials , i.e. as solutions of a second order linear differential equation with polynomial coefficients, the so called Nikiforov-Uvarov approach (see [21]).The third one is based in the Pearson equation which satisfies the symmetric factor for the above differential equation. This idea appears in several papers but the basic theory was developed by P. Maroni.The structure of this paper is as follows: The first section contains material of preliminary and introductory character. Instead of the derivative operator, we use the q-operator H q introduced by Hahn [7]. In particular, we define a H q −semiclassical linear form u from a functional equation which is the q−difference distributional Pearson one. The second section deals with so-called class of H q −semiclassical linear forms. A criterion for determining it is given. In the third section, we establish the different characterizations of H q −semiclassical linear forms. We can characterize a H q −semiclassical linear form through the fact that its Stieltjes function satisfies a first order linear q−difference equation with polynomial coefficients. A second characterization is the so-called structure relation that the polynomials {P n } n≥0 orthogonal with respect to u satisfy. It is deduced from theory of finite-type relations between polynomial sequences [19]. A third characterization is the second order linear q−difference equation satisfied by P n+1 , n ≥ 0. Lastly, in section 4 we construct some examples of H q −semiclassical linear forms of class 1 by taking into account a method studied by P. Maroni in [15] for the D-case ( see paragraph 5.1 below ) and by using s...