Strontium ions are of great interest because of their beneficial role in bone remodeling. This paper provides an overview of the present knowledge on the substitution of calcium with strontium in calcium orthophosphates. In particular, attention is focused on the influence of the substitution on the structure, morphology, and stability of calcium orthophosphates, as well as on the impact of strontium-substituted calcium phosphates on biomaterials in bone substitution/repair.