Learners with developmental manifestations in mainstream classrooms often face delays. The influence of parental support and cultural factors on the development of learners with manifestations was examined. Diagnostic research design, universal sampling involving 116 receiving teachers, survey, and multiple linear regression were the method used. The results, showed parental support and cultural factors were high and related to learner’s development, but only cultural factors significantly influenced it. The findings partly support Bronfenbrenner’s Ecological Systems Theory. Future research may explore additional variables such as environment, teacher support, and resources to explain the remaining 61.2% of the variance in learner development; while school leaders may foster culturally responsive programs to enhance better outcomes for learners with manifestations.