A hypergraph is -sparse if no subset spans more than hyperedges. We characterize -sparse hypergraphs in terms of graph theoretic, matroidal and algorithmic properties. We extend several well-known theorems of Haas, Lovász, Nash-Williams, Tutte, and White and Whiteley, linking arboricity of graphs to certain counts on the number of edges. We also address the problem of finding lower-dimensional representations of sparse hypergraphs, and identify a critical behaviour in terms of the sparsity parameters and . Our constructions extend the pebble games of Lee and Streinu from graphs to hypergraphs.