The Coaching Efficacy Scale (CES) measures beliefs coaches have to affect the learning and performance of their athletes. While previous research has provided support for the model of coaching efficacy and the CES as an adequate measure of the construct, these studies have used paid high-school and college coaches. It is possible that the factor structure of the CES may not replicate for volunteer youth sport coaches. The purpose of this study was to explore coaching efficacy sources used by volunteer youth sport coaches. In addition, the validity of the CES was examined, using a 5-point condensed rating scale, among volunteer youth sport coaches before exploring the sources. The study involved 492 volunteer youth sport coaches from various team sports. Confirmatory factor analysis indicated that the CES had an acceptable fit to the data. The sources of coaching efficacy were examined via multivariate multiple regression and canonical correlation. Results indicated that more confident coaches had more extensive playing and coaching backgrounds, felt their players improved more throughout the season, and perceived more support than did less confident coaches, particularly in regard to technique and game strategy efficacy.