Motivation is a critical factor influencing students’ academic performance and persistence in learning. However, many learners experience challenges sustaining motivation throughout a school term. This study explored the written note ticket intervention as a practical, low-cost method of enhancing learner motivation and performance among Grade 11 STEM students. A mixed-methods design was employed, combining quantitative and qualitative approaches. Twenty-seven (27) STEM learners participated in pre- and post-intervention surveys using a five-item Likert-type motivation scale, and their academic performance was compared against the wider Grade 11 cohort (n = 224). Focus group discussions further captured learners’ perceptions of the intervention. Statistical analysis included descriptive measures, paired-samples t-test, and Cohen’s d for effect size. Findings revealed a significant increase in learners’ motivation levels after the intervention (t = 14.60, p < .001), with Cohen’s d indicating a large practical effect. Qualitative data highlighted that learners valued the consistency, empathy, and personalized nature of the feedback provided through the note tickets. Additionally, the STEM learners’ academic performance (M = 90.89) was significantly higher than the general Grade 11 average (M = 85.64). The study concludes that the written note ticket intervention effectively enhances student motivation and supports improved academic outcomes. Its low cost and scalability make it a promising practice for broader implementation. The research recommends that teachers integrate reflective feedback mechanisms into their classroom practice, administrators provide professional development on motivational strategies, and curriculum developers consider embedding such approaches into learning frameworks.