Background: The development of early childhood naturalist intelligence has not been optimal due to the limited implementation of nature-based learning within the school environment, resulting in children having fewer opportunities to interact directly with nature and develop environmental awareness. Objective: This study aims to examine the effect of the Forest School approach on improving early childhood naturalist intelligence. Methods: This research employed a quantitative approach with an experimental method using a one-group pretest-posttest design. The participants consisted of 15 children from group B at Akhlakul Karimah Kindergarten, Gowa Regency, selected through purposive sampling. Data were collected through observation and documentation using instruments that had been tested for validity and reliability. Data analysis was conducted using descriptive statistics and the Wilcoxon Signed Rank Test, with a significance value (Asymp. Sig. 2-tailed) of 0.001. This significance value is less than 0.05 (0.001 < 0.05). Results: The findings indicate that the implementation of the Forest School approach has a significant effect on children’s naturalist intelligence. This is evidenced by improvements in children’s abilities to recognize, observe, classify, and demonstrate care for the environment after receiving the treatment. Additionally, during the learning process, children showed increased activeness, independence, and a higher level of curiosity. Conclusion: The Forest School approach is proven to be an effective learning strategy in enhancing early childhood naturalist intelligence through direct, meaningful, and nature-based learning experiences, thereby supporting more holistic child development