Girija Vaidyanathan is a retired IAS officer of the Tamil Nadu cadre, and the fourth and longest-serving woman Chief Secretary to the Government of Tamil Nadu, having held the post from December 2016 to June 2019. Belonging to the 1981 batch, Vaidyanathan previously served as the Commissioner of Land Administration in the rank of Additional Chief Secretary. She is known for her work in streamlining the public health system in Tamil Nadu as the Health Secretary in two stints, from 2001–02 and 2011–12, particularly through implementation of innovative schemes for maternal and child health. She was also Mission Director of the National Rural Health Mission, as well as Mission Director of the State Health Society when Tamil Nadu won the award for best performance among the non-empowered action group states. In a long career spanning 38 years, Vaidyanathan has worked in various capacities in the Finance department and headed key departments such as Health and Family Welfare, Nutrition, Environment, Pollution Control, School Education, Civil Supplies and Land Administration. She holds a master’s in physics and a Doctorate in Health Policy from the Indian Institute of Technology, Madras.