The n-3 docosapentaenoic acid (n-3 DPA) is less studied n-3 long-chain polyunsaturated fatty acid (LCPUFA), compared to its counterparts eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Present in food sources in non-negligible quantities, as well as in human milk, dietary n-3 DPA is of current interest both for its ability to increase EPA and DHA tissue status and for its specific or shared biological effects. Indeed, some evidence showed that dietary n-3 DPA is a source of EPA and slightly DHA in the major metabolic organs. n-3 DPA is also the precursor of a large panel of lipid mediators (protectins, resolvins, maresins, isoprostanes) principally implicated in the pro-resolution of the inflammation with specific effects compared to the other n-3 LCPUFA. Recent results showed that n-3 DPA is implied in the improvement of cardiovascular and metabolic disease risk markers, especially plasma lipid parameters, platelet aggregation, insulin sensitivity and cellular plasticity. Moreover, n-3 DPA is the most abundant n-3 LCPUFA in the brain after DHA and it could be specifically beneficial for elderly neuroprotection, and early-life development. These results led to the development of two drugs specifically containing n-3 DPA. This review summarizes the different knowledge about n-3 DPA direct and indirect sources, availability and purification methods, focusing thereafter on the recent findings showing n-3 DPA relationship with fatty acid metabolism, lipid mediators, Finally, the n-3 DPA biological and pharmacological effects are described.