This study was designed to measure and compare individual supervision to triadic supervision in promoting counselor effectiveness and counselor development. During individual supervision, one counselor met with one supervisor for an hour. Two models of triadic supervision were created for this study: Split Focus and Single Focus. Triadic consists of two supervisees and one supervisor meeting for one hour. During the Split Focus, 30 minutes was allocated to each counselor for supervision. During the Single Focus, the whole hour was spent supervising only one of the counselors. The next week, the whole hour was spent supervising the other counselor. Three comparison groups were employed to determine the effectiveness of the three supervision models. An instrument was used to evaluate counselor effectiveness and another instrument was used to evaluate counselor development. 47 masters-level counseling students enrolled in practicum participated in this study. The practicum met for 16 weeks. Each counselor filled out a Supervisee Levels Questionnaire-Revised at the beginning (pre-test) and at the end (post-test) of the semester. This instrument determined the counselor's developmental growth. Each counselor submitted a tape of a counseling session at the beginning (pre-tape) and at the end (post-tape) of the semester. The tape was rated on-site by the doctoral supervisor utilizing the Counselor Rating Form-Short. An objective rater also rated the submitted tapes utilizing the same instrument. The instrument determines counselor effectiveness. At the end of the study, an Analysis of Covariance determined that the three supervision models did differ in developmental growth. The Split Focus grew significantly compared to Single Focus and compared to Individual supervision. However, the Single Focus grew significantly on the factor self and other awareness compared to Individual. In terms of effectiveness, an Analysis of Covariance determined that the three supervision models did not differ significantly.