["Psychology in the Schools, EarlyView. ", "\nABSTRACT\nAs concerns for rising rates of youth suicide and suicidal thoughts and behaviors continue to grow, there is a need to prioritize school‐based suicide prevention programs. Despite evidence documenting the effectiveness of school‐based prevention programs for reducing suicide‐related risk in adolescents, schools face numerous barriers to successfully implementing programs with fidelity. Therefore, the present study aimed to identify tailored implementation strategies to increase fidelity and sustainability of school‐based suicide prevention programs. We first used focus groups to explore school personnel (N = 16) perspectives on barriers and facilitators of the implementation of Sources of Strength, an evidence‐based suicide prevention program. Next, we conducted a co‐design session with nine of these participants to identify actionable implementation strategies based on school personnel input. Last, to translate findings into practice, we developed an implementation toolkit to support delivery of Sources of Strength and other upstream suicide prevention programs. Findings inform actionable strategies for ensuring mechanisms for change (e.g., using multiple approaches for identifying Peer Leaders) and sustaining champions (e.g., proactive recruitment of adults into distributed leadership) for overcoming some of the typical implementation barriers school personnel may face when implementing Sources of Strength or other upstream suicide prevention programs."]