Background and Objective: Elementary school is a critical developmental stage during which the emotional and social foundations of children are formed. Deficiencies in these domains may adversely affect their mental health. Therefore, the present study aimed to investigate the effectiveness of Reality Therapy on positive affect, negative affect, and social interest among students in Grades 4–6 of elementary school. Methods: This study employed a quasi-experimental design with pretest, posttest, and follow-up assessments, along with a control group. The statistical population consisted of all fourth- to sixth-grade elementary school students in Mobarakeh County, Iran, and one of their parents during the 2025–2026 academic year. Thirty children and their mothers were selected through convenience sampling and were randomly assigned to either an experimental group (n = 15) or a control group (n = 15). The experimental group participated in ten weekly 60-minute Reality Therapy sessions, which included training for both the children and their mothers. Data were collected using the Positive and Negative Affect Scale for Children (PANAS-C), developed by Laurent et al. (1999), and the Social Interest Scale for Children (SISIC), developed by Alizadeh et al. (2015).Data were analyzed using repeated-measures analysis of variance (ANOVA) in SPSS version 26. Results: The findings indicated that, compared with the control group, Reality Therapy significantly increased positive affect and social interest while significantly reducing negative affect among students in the experimental group (p < .01). These effects remained stable at the follow-up assessment. Conclusion: The findings suggest that Reality Therapy, by emphasizing personal responsibility and the fulfillment of basic psychological needs, is an effective intervention for enhancing children's emotional well-being and strengthening their social connectedness in educational settings. Therefore, this approach can be recommended as an effective strategy for increasing positive affect, reducing negative affect, and promoting social interest among elementary school students.