The primary purposes of this study were to establish the validity of the Gibson and Dembo (1984) teacher efficacy scale (modified for use by resource-room teachers) and to examine the association between resource-room teacher efficacy and the reported frequency and utility of the instructional supervision these teachers received. The 580 Maine resource teachers who participated completed a survey rating teacher efficacy (personal and general) and the frequency and utility of supervision they received. Results indicate that the perceived utility of supervision, not its frequency, significantly predicted teacher efficacy in this group. That is, teachers who felt their supervision was "helpful" tended to report a higher sense of teacher efficacy than those who reported less positive views of the supervision they received. This finding held irrespective of sex, age, or job satisfaction, each of which significantly and positively predicted teacher efficacy in its own right. Two tables provide descriptive statistics and the multiple regression analysis. A modified 30-item teacher efficacy scale is appended. (SM)