This article describes the content validation of the Transitioning Learners to Calculus in Community Colleges Institutional Self-Assessment Tool. The instrument comprises five content areas, each with an associated set of items representing practices to promote the success of underrepresented racially minoritized (URM) students as they transition into and through mathematics courses required for degrees in science, technology, engineering, and mathematics (STEM). Five subject matter experts participated in the content validation. Scale-level index scores for each content area were above .85, and 18 of 22 items met the content validity index threshold of 1.0. The instrument has demonstrated strong content validity and is recommended for mathematics programs in community colleges to self-assess the degree to which they have implemented these practices and to identify next steps to enhance their support of URM students in mathematics courses required for STEM degrees.