The problem of Zarankiewicz asks for the maximum number of edges in a bipartite graph on n vertices which does not contain the complete bipartite graph K k,k as a subgraph. A classical theorem due to Kővári, Sós, and Turán says that this number of edges is O n 2−1/k . An important variant of this problem is the analogous question in bipartite graphs with VC-dimension at most d, where d is a fixed integer such that k ≥ d ≥ 2. A remarkable result of Fox, Pach, Sheffer, Suk, and Zahl with multiple applications in incidence geometry shows that, under this additional hypothesis, the number of edges in a bipartite graph on n vertices and with no copy of K k,k as a subgraph must be O n 2−1/d . This theorem is sharp when k = d = 2, because by design any K 2,2 -free graph automatically has V C-dimension at most 2, and there are well-known examples of such graphs with Ω n 3/2 edges. However, it turns out this phenomenon no longer carries through for any larger d.We show the following improved result: the maximum number of edges in bipartite graphs with no copies of K k,k and VC-dimension at most d is o(n 2−1/d ), for every k ≥ d ≥ 3.