Assessment of class participation (ACP) has been widely adopted in higher education because, presumably, it motivates students and facilitates active learning. Despite its popularity, evidence regarding how teachers perceive and implement ACP has remained largely anecdotal. This study explored teachers' perceptions and practices of ACP based on a survey administered to 1036 university English teachers and a case study of three participants in China. Findings reveal that the teachers perceived ACP as necessary for engaging students in language learning, but had some confusion over its reliable and transparent implementation. Their challenges in ACP practice include biased and unethical grading, absence of guidelines, and difficulty with consistent tracking and recording of class performance. Discussions revolve around ACP legitimacy and transparency, cognitive considerations of constructs in assessment criteria, and ethical dilemmas posed by power relations in the workplace. This paper concludes with implications for policy, practice, and professional development of effective ACP.