The Physical Research Laboratory (PRL) is a National Research Institute for space and allied sciences, supported mainly by Department of Space, Government of India. This research laboratory has ongoing research programmes in astronomy and astrophysics, atmospheric sciences and aeronomy, Earth sciences, Solar System studies and theoretical physics.[1] It manages the Udaipur Solar Observatory and is located in Ahmedabad.

Known as the cradle of space sciences in India, the Physical Research Laboratory (PRL) was founded on 11 November 1947[2] by Dr. Vikram Sarabhai. PRL had a modest beginning at his residence, the RETREAT, with research on cosmic rays.

The institute was formally established at the M.G. Science Institute, Ahmedabad, with support from the Karmkshetra Educational Foundation and the Ahmedabad Education Society. Prof. Kalpathi Ramakrishna Ramanathan was the first Director of the institute. The initial focus was research on cosmic rays and the properties of the upper atmosphere. Research areas were expanded to include theoretical physics and radio physics later with grants from the Atomic Energy Commission.

Today[when?] PRL is involved in research, related to five major fields of science. PRL is also instrumental in the PLANEX planetary science and exploration programme.