Letter formation is recognized as a crucial aspect in early literacy, prompting this study to determine the effectiveness of rainbow writing in enhancing the letter skills of kindergarten pupils. A quasi-experimental research design was utilized, with the control group receiving traditional instruction and the experimental group receiving rainbow writing as an intervention. The pre-test results indicated that the respondents in the control group got a grade of 83.13% and the experimental group with 77.08% which did not meet the expectation of a passing score. Post-test results however, revealed a minimal improvement in the student’s performance with a grade of 86.30% in the control group indicating a very satisfactory remarks and the experimental group’s performance significantly improved compared to the control group 96.88% indicating an outstanding remarks. This study has important implications for educators and early childhood education (ECE) institutions seeking to address the enhancement of letter formation among kindergarten pupils with the use of rainbow writing for it provides a rich and memorable learning environment for young learners through tracing and writing letters using various colors, children can enhance their muscle memory and proprioception, making the process of letter formation more memorable and meaningful.