•Implementation of a values-engaged evaluation approach was examined.•Evaluators explicitly attended to culture, diversity, and equity.•The case setting was the evaluation of a multi-year STEM program.•Evaluators were most successful when using formal and informal communication. Evaluation must attend meaningfully and respectfully to issues of culture, race, diversity, power, and equity. This attention is especially critical within the evaluation of science, technology, engineering, and mathematics (STEM) educational programming, which has an explicit agenda of broadening participation. The purpose of this article is to report lessons learned from the implementation of a values-engaged, educative (Greene et al., 2006) evaluation within a multi-year STEM education program setting. This meta-evaluation employed a case study design using data from evaluator weekly systematic reflections, review of evaluation and program artifacts, stakeholder interviews, and peer review and assessment. The main findings from this study are (a) explicit attention to culture, diversity, and equity was initially challenged by organizational culture and under-developed evaluator–stakeholder professional relationship and (b) evidence of successful engagement of culture, diversity, and equity emerged in formal evaluation criteria and documents, and informal dialogue and discussion with stakeholders. The paper concludes with lessons learned and implications for practice.