In this quantitative study the author examined the relationship between the perceived level of principal supervision and support to the perceived self-efficacy of K-12 teachers in a suburban public school district. The impact of perceived self-efficacy upon the commitment to remain in teaching was also considered. Finally the differential relationship between perceived principal support and supervision to commitment to remain in teaching was compared for novice and experienced teachers. This study did not introduce an experimental treatment but surveyed teachers in their naturally occurring situation. Teachers in a suburban school district filled out a 40-item online questionnaire assessing their perceptions of the level of principal support and supervision they receive along with their perceived self-efficacy and their level of commitment to remain in teaching. 152 questionnaires were completed for a return rate of 17.1%. Correlations were run for each of the research questions. Weak positive correlations were found to exist between perceived self-efficacy and principal support (r =0.164, p < 0.05, N = 152) and principal supervision (r = 0.324, p < 0.01, N = 152). Weak correlations were also found for commitment to remain in teaching, for experienced teachers, and principal support (r = 0.354, p < 0.01, n = 144) and principal supervision (r = 0.258, p < 0.01, n = 144). The sample population of novice teachers was small, n = 8, and yielded no significant results. Suggestions for further research include investigations into alternative methods of principal supervision and collecting measurements of collective self-efficacy. [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://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]