Introduction: Myocardial Infarction (MI) triggers an inflammatory response associated with cardiac wound healing. T-regulatory cells (Tregs) play a crucial role in the MI heart during this inflammatory response via their regulation of cardiac repair and function. Stimulating and sustaining the pro-reparative T cell response after MI would aid in preserving cardiac structure and function. Cortical Bone derived Stem Cells (CBSCs) possess a diverse array of inflammatory signaling molecules that can influence the inflammatory microenvironment of the heart after MI. A paracrine factor, Osteoprotegerin (OPG), is abundantly present in CBSCs, but it is unknown if OPG can mediate Tregs in myocardial injury. Hypothesis: CBSCs-derived Osteoprotegerin can regulate cardiac wound healing post-MI by modulating T cell response. Methods and Results: T cells exposed to CBSC secretome underwent an upregulation of a Treg population (p≤0.0001) characterized by the expression of Tumor Necrosis Factor Receptor II (TNFRII). Further investigation into the CBSC secretome highlighted OPG as a potent signaling molecule responsible for inducing TNFRII+ Tregs (p≤0.0001) measured by FACS analysis. siRNA-mediated depletion of OPG studies showed compromised TNFRII+ Treg induction (p≤0.0001). In vivo studies, adult FoxP3-GFP (12-16 week) mice underwent left anterior descending artery ligation followed by intramyocardial injection of CBSCs, Mesenchymal Stem Cells (MSCs), or vehicle (saline) along the infarct border zone. Resident T-lymphocyte populations were assessed at 1- and 8-weeks post-MI via flow cytometry. CBSC-treated hearts yielded a greater prevalence of TNFRII+ Tregs at 1- and 8-weeks following MI compared to MSCs (p≤0.01; p≤0.0001) and vehicle (p≤0.0001; p≤0.05). CBSC induction following MI reduced infarct size compared to the vehicle (p≤0.05). Ablation of the Treg population in the ischemic zone following MI increased infarct size and solicited adverse cardiac remodeling (p≤0.05). Conclusion: Osteoprotegerin can promote cardiac wound healing by facilitating the expansion and preservation of pro-reparative TNFRII+ Tregs.