The aim of this study was to examine teachers' self-assessments of their ability to create a positive classroom environment. The study used a survey method, and the sample was composed of 260 teachers who worked in the province of Tokat in Turkey in the 2017-2018 academic year. Research data were collected through the Class Control Index developed by Howard (1978) and translated into Turkish by Özden (2005). To analyze the data, the researchers used the t-test, one-way analysis of variance, Kruskal-Wallis H and Mann-Whitney U tests, and Pearson Moments Multiplication Correlation Coefficient. According to the results, teachers have high self-assessments of their ability to create a positive classroom environment. Primary school teachers had higher self-assessment scores than middle and high school teachers. Women's scores were higher than men's, classroom teachers had the highest scores, and information technology teachers had the lowest. In addition, there was no significant difference in terms of age, occupational seniority, postgraduate education, type of school (for high school teachers), department from which teachers graduated, or classroom management. [Cover Title: "Investigation of Teachers' Self-Assessment to Create a Positive Classroom Environment."]