The activities carried out in the out-of-school environments are important for enriching the learning experiences of the students, socializing the students and providing permanent learning. The purpose of this research is to examine conducted postgraduate studies in Turkey regarding out of school learning environments with the content analysis method. A total of 40 (8 Ph.D., 32 graduate thesis) studies have been analyzed in the relevant area. The studies were examined within the framework of the subject area, methodology, sampling, data collection tools, data analysis methods. Results showed that research studies was more prevalent in the field of science. Science centers, museums, and zoos are generally preferred within the application areas. It has also found that the studies are mostly carried out with secondary school students and teachers. Generally, interview forms, likert type scales, and success tests were used as data collection tools and descriptive and predictive data analyzes were used as data analysis methods. When studies are examined in terms of research approaches, quantitative and mixed approaches appear to be the first. Another result is that learning in non-formal settings enhances student achievement, develops scientific process skills, and positively affects attitudes and motivations towards the course.