- Department of Adi Dravidar and Tribal Welfare (Tamil Nadu)
- Department of Agriculture (Tamil Nadu)
- Department of Animal Husbandry, Dairying and Fisheries (Tamil Nadu)
- Department of Backward Classes, Most Backward Classes and Minorities Welfare (Tamil Nadu)
- Department of Co-operation, Food and Consumer Protection (Tamil Nadu)
- Department of Commercial Taxes and Registration (Tamil Nadu)
- Department of Energy (Tamil Nadu)
- Department of Environment and Forests (Tamil Nadu)
- Department of Finance (Tamil Nadu)
- Department of Handlooms, Handicrafts, Textiles and Khadi (Tamil Nadu)
- Department of Health and Family Welfare (Tamil Nadu)
- Department of Higher Education (Tamil Nadu)
- Department of Highways and Minor Ports (Tamil Nadu)
- Department of Home, Prohibition and Excise (Tamil Nadu)
- Department of Industries (Tamil Nadu)
- Department of Information Technology (Tamil Nadu)
- Department of Labour and Employment (Tamil Nadu)
- Department of Law (Tamil Nadu)
- Department of Legislative Assembly (Tamil Nadu)
- Department of Municipal Administration and Water Supply (Tamil Nadu)
- Department of Micro, Small and Medium Enterprises (Tamil Nadu) (formerly Small Industries Department )
- Department of Personnel and Administrative Reforms (Tamil Nadu)
- Department of Planning, Development and Special Initiatives (Tamil Nadu)
- Department of Public (Tamil Nadu)
- Department of Public Works (Tamil Nadu)
- Department of Revenue (Tamil Nadu)
- Department of Rural Development and Panchayat (Tamil Nadu)
- Department of School Education (Tamil Nadu)
- Department of Social Reforms Department (Tamil Nadu)
- Department of Social Welfare and Nutritious Meal Programme (Tamil Nadu)
- Department of Special Programme Implementation (Tamil Nadu)
- Department of Tourism and Culture (Tamil Nadu)
- Department of Tamil Development, Religious Endowments and Information (Tamil Nadu)
- Department of Transport (Tamil Nadu)
- Department of Youth Welfare and Sports (Tamil Nadu)
- Department of Welfare of Differently Abled Persons (Tamil Nadu)
There are several laws under 40 Secretariat Departments as follows
• Ramachandran
