This study, grounded in Self-Efficacy Theory, investigated classroom teachers' self-efficacy changes related to teaching healthy behaviour content after participating in ongoing workshops. Participants were 50 male and female teachers at the primary (n = 17) and secondary (n = 33) levels from two schools in one Native American community. Teacher participants completed two previously validated teaching efficacy instruments. Results showed that student healthy behaviour knowledge scores were linearly related to increases in teacher efficacy. Teacher efficacy increased in a linear pattern (education efficacy) or fluctuated (healthy behaviour content). Classroom teachers can help to create develop healthy and active schools. (Contains 1 figure and 1 table.)