Gasper & Rahman's multivariate q-Racah polynomials are shown to arise as connection coefficients between families of multivariate q-Hahn or q-Jacobi polynomials. The families of q-Hahn polynomials are constructed as nested Clebsch-Gordan coefficients for the positive-discrete series representations of the quantum algebra su q (1,1). This gives an interpretation of the multivariate q-Racah polynomials in terms of 3n j symbols. It is shown that the families of q-Hahn polynomials also arise in wavefunctions of q-deformed quantum Calogero-Gaudin superintegrable systems.Keywords: multivariate q-Racah polynomials, representations of su q (1,1), Clebsch-Gordan coefficients, superintegrable systems.Coupling coefficients of su q (1, 1) & multivariate q-Racah polynomials bases of multivariate Jacobi polynomials on the simplex [5] and used this to compute connection coefficients for families of discrete classical orthogonal polynomials studied in [19], as well as for orthogonal polynomials on balls and spheres. In [18], Iliev has established the connection between the bispectral operators for the multivariate Racah polynomials and the symmetries of the generic superintegrable system on the d-sphere. In [2], De Bie, Genest, van de Vijver and Vinet have unveiled the relationship between this superintegrable model, d-fold tensor product representations of su(1, 1) and the higher rank Racah algebra. See also [8,29,30].Many of these results have yet to be extended to the q-deformed case. The interpretation of the univariate q-Racah polynomials as 6 j coefficients for the quantum algebra su q (1, 1) is well known [37], as is its relation with the Zhedanov algebra and the operators involved in the bispectrality of the one-variable q-Racah polynomials [16,38]. Dunkl has also shown in [4] that these polynomials arise as connection coefficients between bases of two-variable q-Jacobi or q-Hahn polynomials. On the multivariate side, Rosengren has observed that q-Hahn polynomials arise by considering nested Clebsch-Gordan coefficients for su q (1, 1) and derived some explicit formulas [31]. Moreover, Scarabotti has examined similar families of multivariate q-Hahn polynomials associated to binary trees and their connection coefficients [32].Nevertheless, the identification of the multivariate q-Racah polynomials as 3n j coefficients of the quantum algebra su q (1, 1) has not been achieved. Moreover, the connection between q-Racah polynomials, both univariate and multivariate, and superintegrable systems remains to be determined. The present paper addresses these questions. As stated above, it will be shown that Gasper & Rahman's multivariate q-Racah polynomials arise as connection coefficients between bases of multivariate orthogonal q-Hahn or q-Jacobi polynomials. The bases will be constructed using the nested Clebsch-Gordan coefficients for multifold tensor product representations of su q (1, 1), which will provide the exact interpretation of the multivariate q-Racah polynomials in terms of coupling coefficients for that quantum algebr...