The Consultation Self-Efficacy Scale (CSES) was developed and validated to assess school psychologists' perceptions of self-efficacy for engaging in school-based consultation. A pilot study with graduate students (N = 92) indicated high internal consistency (a = 0.99) and provided evidence of discriminant validity, as a group with more consultation experience had significantly higher total self-efficacy scores (M = 512.25) than a moderately experienced group (M = 437.35). Subsequently, a sample of 347 practicing school psychologists completed a revised CSES, consistently endorsing moderate to high levels of consultation self-efficacy (M = 404.08, SD = 51.73). Although consultation self-efficacy was hypothesized to be a multidimensional construct, exploratory factor analysis indicated a single-factor structure. Construct validity of the instrument was supported by significant correlations between school psychologists' consultation self-efficacy ratings and perceptions of their ability to respond to hypothetical consultation referral problems (r = 0.69, p < 0.01), and regression analysis found that years of experience and time spent consulting with teachers predicted psychologists' self-efficacy scores.