This research examined master's theses on STEM and STEAM (science, technology, engineering, arts, and mathematics) in early childhood education published in Turkey. The data in the research consisted of master's theses on STEM and STEAM in early childhood education published in full text in the Higher Education Council (YÖK) Thesis Center database. The PRISMA method was used in reporting the theses. The research material consists of 59 graduate theses on STEM+STEAM that are fully accessible from the YOK Thesis Center database, according to the convenience sampling method. Descriptive content analysis was performed on the theses using the Paper Classification Form (PCF). The validity and reliability of the theses were checked in the analysis. According to the results obtained, most of the theses on STEM+STEAM in early childhood education are master's theses, depending on the program in which they were published. It was observed that theses on STEM+STEAM predominantly focused on the theme of scientific process skills. When examined in terms of research methodology, it was found that theses frequently used a semi-experimental design. It was determined that convenient sampling, purposive sampling, and random sampling were often preferred in sampling methods in theses. It was observed that children were frequently included in the sample group. When data collection tools were examined, it was found that theses often used activities related to the STEM+STEAM approach, as well as scales, interviews, and observation forms. In conclusion, the trend of theses on STEM+STEAM in the field of early childhood education was discussed within the scope of the literature.