Learning activities employed in out-of-school learning activities (OOSLA) provide students with a different learning experience while enabling teachers to discover, implement, and evaluate different teaching approaches. This study intends to investigate the self-efficacy beliefs levels of teachers as regards OOSLA and whether these self-efficacy levels differ significantly depending on their gender, graduated faculty, educational status, seniority, and department graduated from. It adopts the descriptive survey design. The sample is composed of 308 teachers. The data were collected utilizing the "Teachers' Self-Efficacy Beliefs Toward Out-of-School Learning Activities Scale''. Parametric test statistics were used in data analysis. The results revealed that teachers had a high level of self-efficacy beliefs regarding OOSLA and that gender was not a determinant of teachers' self-efficacy beliefs. It was also found that the participants who completed graduate studies had firmer self-efficacy beliefs than those who did not. The teachers with 21 years and above of teaching experience had higher self-efficacy levels than those with 6-10 and 11-15 years of teaching experience. On the other hand, graduates of mathematics and science education departments had lower self-efficacy levels than primary education, Turkish education, and social science education departments. Finally, researchers recommend encouraging pursuing graduate studies, collaborating with experienced teachers, eliminating institutional obstacles to out-of-school activities, and supporting teachers in increasing their self-efficacy regarding out-of-school learning activities.