We define a class of probability distributions that we call simplicial mixture models, inspired by simplicial complexes from algebraic topology. The parameters of these distributions represent their topology and we show that it is possible and feasible to fit topological structure to data using a maximum-likelihood approach. We prove under reasonable assumptions that with a fixed number of vertices a distribution can be approximated arbitrarily closely by a simplicial mixture model when using enough simplices. Even if the topology is not of primary interest, when using a model that takes the topology of the data into account the vertex positions are good candidates for archetype/endmember vectors in unmixing problems.