Mental health continues to be a concern for individuals of all ages in the United States. Teachers and students are greatly affected by the impact of mental health related issues. Teachers perform in less than effective ways and student success is hindered when distress is experienced at school. Professional school counselors are in an excellent position to assist students and teachers in becoming more mentally healthy by providing interventions derived from counseling theory. A quasi-experimental design was used in the following field study to examine the impact of two teacher interventions based on Social Cognitive Theory and Rational Emotive Behavior Therapy. Additionally, the relationships of several of the constructs of these theories were explored. Teachers (n = 42) were assigned to one of three conditions; face-to-face, on-line, or no treatment waiting list control. Both treatments spanned an eight-week period. Pre-tests and posttests were incorporated to measure the relationships of the constructs under investigation and the effectiveness of the interventions. Overall, the face-to-face intervention was found to be more effective in reducing irrational beliefs than the online treatment. Analyses of variance indicated significant differences between the face-to-face and control groups for irrational beliefs, specifically self-downing attitudes and authoritarian attitudes toward students. However, significant differences across groups were not found for efficacy beliefs. Furthermore, neither depression, anxiety, or stress were reduced as a result of exposure to either treatment. Regardless of condition, teachers indicated similar thoughts, feelings, and behaviors when responding to hypothetical classroom scenarios. Self-blaming thoughts did emerge from the control group in response to efficaciousness related to the classroom scenarios. Moderate to strong relationships were found amongst several of the constructs examined in this study. Irrational beliefs were found to be negatively related to general efficacy beliefs, while positively correlated with depression, anxiety, and stress. Irrational beliefs rooted in worry were found to be significantly related to depression, anxiety and stress. Additionally, general self-efficacy and depression, anxiety, and stress were negatively correlated. The findings of this study indicate a need for further exploration of the relationships between irrational beliefs, self-efficacy, and depression, anxiety, and stress. Furthermore, continued development and implementation of mental health interventions for teachers, rooted in Rational Emotive Behavior Therapy and Social Cognitive Theory, is warranted. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]