Three studies were conducted to (a) re-examine the internal properties of Roach's Power Base Measure (PBM), (b) test the PBM for measurement invariance across different samples, and (c) develop an alternative measure of observable teacher behaviors that communicate power in the classroom. Results of Studies 1 and 2 provide some support for the PBM, as confirmatory factor analyses supported the hypothesized item loadings for each dimension and demonstrated strong metric invariance. Aggregate scores for each dimension of the PBM, however, produced poor model fit when hypothesized to represent the latent construct of teacher power. Results of Study 3 yielded a new measure of teacher power, the Teacher Power Use Scale. Validity estimates for both measures are offered, and theoretical implications are discussed. (Contains 4 tables.)