This study leveraged data from a 40-school randomized controlled trial to understand the cost of coaching to support implementation of evidence-based programs (EBPs) through a multi-tiered system of supports for behavior (MTSS-B) model. Coach activity log data were utilized to generate the annual average, per school, costs of coaching of $8,198. The cost of school personnel time for coaching was estimated to be $3,028. Data on coach-rated administrator buy-in, school MTSS-B engagement, and implementation infrastructure and capacity were also collected and found to be associated with coaching activities. Notably, coaches did not spend significantly different amounts of time in schools using few EBPs relative to more EBPs, indicating some inefficiency in the use of coaches' time. These findings highlight the often-overlooked resources needed to support EBP implementation in schools. [This paper will be published in "Administration and Policy in Mental Health and Mental Health Services Research."]