India’s Siddi are a large Afro-descendant community of tribes with an estimated 150,000 members in the country, based for centuries in rural areas of Goa, Karnataka, Maharashtra, Andhra Pradesh and Gujarat. Very few Siddi families live in other parts of the country. The age of 6 to 12 years is an active and dynamic period of physical growth as well as of mental health in school children. It is well established that nutritional status is a major determinant of the health and well-being among children. The present study was conducted with objectives, to know the nutritional status and to assess the impact of intervention programme on cognitive development of school children of Siddi tribe. Random sampling technique was used to select the children in the age group of 5 years to 10 years for the study. The questionnaire and assessment methods were predominantly used to collect the data. Ravens Color Progressive Matrices and self-structured questionnaire were used to elicit the information. The results showed that severe level of stunting was observed among 5 to 7 years of age group (44.16%) compared to 8 to 9 years old children (24.5%). About 21.53% of the respondents moderately underweight in 5 to 7 years whereas 32.07% of 8- to 9-year-old belonged severe underweight category. According to cognitive development of school children, 27% had definitely above the average level of cognitive development while 26.27% of them were intellectually average and intellectually superior level of cognitive development followed by 23% children had definitely below the average level of cognitive development. Three months nutrition and activity-based intervention was given to school children. The intervention findings revealed that significant improvement of cognitive development of children and significant increase in weight status was observed in intervention group but no such improvement was observed in control group children. Hence nutritional status of the child shows positive correlation with weight, height, MUAC and BMI. This indicates cognitive development was impacting on nutritional status of the children. Hence there is a need of awareness programme on healthy and nutritious food to maintain the optimum nutritional status of the children and educational programme regarding nutrients to improve the cognitive development.