This study builds validity evidence for the Student Interest Scale and Student Engagement Scale. Confirmatory factor analysis indicates that the factor structures of the new measures are stable, reliable, and valid. The results indicate a positive association between student emotional and cognitive interest and engagement, providing initial evidence for construct validity. Results reveal positive relationships between student interest, learner empowerment, motivation, and affective learning, offering evidence of convergent validity. Analyses reveal that the Student Interest Scale is distinct from Weber, Martin, and Cayanus' (2005) Learner Empowerment Scale, McCroskey's (1994) Affective Learning Scale, and Christophel's (1990) Motivation Scale, while the Student Engagement Scale is distinct from Frymier and Houser's (1999) Learning Indicators Scale, providing discriminant validity evidence.