No. 20 Squadron was raised initially as a flight at PAF Base, Masroor in March 1956. The unit was upgraded to squadron status within a year of its formation. Its first CO being Flight Lieutenant Zulfiqar A Khan. The squadron was number-plated in June 1972 and was reactivated in June 1977. Initially the squadron was equipped with RT-33 photo recce aircraft and its role was day photographic survey and reconnaissance.

In June 1977, the squadron was reequipped with French-built Mirage-III RP aircraft and was assigned the role of tactical attack and reconnaissance during both day and night. In May 1986, the unit went through another re-equipment, this time with Chinese built F-6 aircraft, and was assigned the role of air superiority.

One of the earliest tasks of the Squadron was to conduct a photographic survey of the northern areas with its RT-33s. These missions were undertaken over difficult and uncharted terrain, and often in marginal weather conditions. For his personal contribution as well as for the performance of the unit, the squadron commander, Flight Lieutenant M Anwar Saeed was awarded Tamgha-i-Basalat.

In 1963 the squadron made a major contribution towards an amicable demarcation of the border between Pakistan and China by providing detailed and accurate photographic data. Despite its magnitude the task was completed in one month and in recognition of the unit's excellent performance the officer commanding Squadron Leader A Sattar Chaudhry was awarded Sitara-i-Basalat.

In 1964, No 20 Squadron undertook a task of immense national importance when it photographed the major river basins of the country to facilitate the work of the World Bank's Indus Basin Project. The unit can justly be proud of its contribution towards the siting of Mangla and Tarbela dams, the two largest the country.

The squadron flew 24 tactical reconnaissance missions during the 1965 war. In spite of the great disadvantage of operating a slow and unarmed aircraft, the pilots of 20 Squadron operated well inside enemy territory and photographed vital targets both for the Pakistan Air Force and the Pakistan Army.

For this courageous performance the squadron commander, Squadron Leader Mir Mubariz Ahmed was awarded Tamgha-i-Basalat. In 1971 a detachment of the squadron was deployed in East Pakistan also to provide photographic intelligence to the army. No. 20 Tactical Attack and Reconnaissance Squadron was presented with the squadron colour by Air Chief Marshal Zulfiqar Ali Khan on 6th April 1978.