This study examined perceptual evaluations of classroom teachers, acoustic measures of their voices ( fundamental frequency [F0], frequency range [F0SD], % jitter, and % shimmer), and behavioral measures (rate, dysfluencies, and episodes of vocal fry). This preliminary study attempted to identify perceptual and acoustic measures that discriminate between effective and less effective classroom teachers. Seven teachers were recorded on audiotape while presenting a 10-12 minute lecture. Voice samples (N > 200) for each teacher were subjected to acoustic analysis. Audiotapes were evaluated by listeners (N = 180), who scale-rated and used an adjective checklist to determine teachers' overall effectiveness. A three-member team evaluated global aspects of voice (e.g., use of pauses, inflections, contours, and phrasing). Results indicated that frequency range, frequency variability, rate, and number of dysfluencies appeared to correlate with perceptual judgments of teaching effectiveness and specific adjective descriptors. F0, % jitter, and % shimmer did not appear to be linked to perceptual judgments. Individual case profiles were established and recommendations were made for future empirical research involving larger samples of teachers.