Plant community composition can impact ecosystem processes via litter feedbacks. Species variation in litter quality may generate different patterns of nutrient supply for plants that are dependent on litter inputs. However, it is not known whether plants grow faster in their own litter, litter from other species, or in litter mixtures from multiple species. To test whether litter identity and mixture status influenced mangrove seedling growth, biomass allocation, and stoichiometry, we performed mesocosm experiments. Two species of mangrove seedlings, Avicennia germinans, black mangrove and Rhizophora mangle, red mangrove, were exposed to all possible combinations of three mangrove litter types and were isolated from all other nutrient inputs. Litter treatments significantly altered seedling growth. Seedlings from both mangrove species grew most rapidly in litter from a different species rather than their own, irrespective of litter chemical quality, decomposition rate, and nitrogen release. Litter mixtures from white and black mangroves caused black mangroves to grow 65% more than expected. Litter treatments did not impact seedling root:shoot ratios or tissue C:N. Our finding that seedlings grow best in litter from other species may indicate a mechanism that helps sustain the coexistence of dominant species.