The objective of the research paper is to analyse the impact of the tribal sub-plan on the socio-economic condition of respondents and examine the impact of the tribal sub-plan on sustainable livelihood, education, and economic security of tribals in Gajapati district, Odisha, India. The study is based on primary and secondary data. Primary data was collected from 02 blocks, viz., Mohana, and R. Udayagiri block under the Gajapati district in 2021. The analysis is based on demographic variables, economic variables, income, occupational structure and educational variables in Gajapati district using descriptive statistics. Tribal education level is very low, no basic facilities, a lack of infrastructure, and no sustainable livelihood; there is economic insecurity among tribal people. All these problems may be eradicated through the tribal sub-plan. The Tribal Sub Plan is a strategic plan that was introduced by the Government of India for the quick socio economic development of Tribal people in India.