Strontium (Sr) is known to stimulate osteogenesis， while inhibiting osteoclastogenesis， thus encouraging research on its application as a therapeutic agent for bone repair/regeneration. It has been suggested that it may possess immunomodulatory properties， which might act synergistically in bone repair/regeneration processes. To further explore this hypothesis we have designed a Sr-hybrid system composed of an in situ forming Sr-crosslinked RGD-alginate hydrogel reinforced with Sr-doped hydroxyapatite (HAp) microspheres and studied its in vitro osteoinductive behaviour and in vivo inflammatory response. The Sr-hybrid scaffold acts as a dual Sr delivery system， showing a cumulative Sr release of ca. 0.3 mM after 15 days. In vitro studies using Srconcentrations within this range (0 to 3 mM Sr) confirmed its ability to induce osteogenic differentiation of mesenchymal stem/stromal cells (MSC)， as well as to reduce osteoclastogenesis and osteoclasts (OC) functionality. In comparison with a similar Sr-free system， the Sr-hybrid system stimulated osteogenic differentiation of MSC， while inhibiting the formation of OC. Implantation in an in vivo model of inflammation， revealed an increase in F4/80/CD206 cells， highlighting its ability to modulate the inflammatory response as a pro-resolution mediator， through M2 macrophage polarization. Therefore， the Sr-hybrid system is potentially an appealing biomaterial for future clinical applications.