Seniors centres play a key role in promoting well-being and social connectivity of older adults. Yet, discussions on how to better align them with primary healthcare are typically led by the healthcare sector, often in isolation and without incorporating perspectives of seniors centres. Hence, the proposed initiative aims to expand the role of seniors centres and their potential impact through strategic collaboration and opportunities for research. By convening key stakeholders, including representatives from four Vancouver-based senior centres and four healthcare providers, we will co-develop a research and practice agenda through five workshops structured around a Theory of Change (TOC) framework. The TOC will guide the creation of long-term goals, identify necessary conditions for success, and establish measurable indicators to track progress and effectiveness. Key intended outcomes are to foster a collaborative approach to integrating seniors centres in shaping healthcare delivery; improve cross-sectoral collaboration to develop insights on how integrated efforts can better support health outcomes for older adults; and establish a research and practice agenda to explore the role of senior centres within primary healthcare.