The 2020–21 PRO14 (also known as the Guinness PRO14 for sponsorship reasons) was the twentieth season of the professional rugby union competition originally known as the Celtic League.

It was the fourth season to be referred to as the PRO14 (the competition was named the Pro12 immediately prior to the addition of two South African teams).

[6][7] On 23 December 2020 it was announced that the 2020-21 PRO14 season would conclude on 27 March 2021 after 16 rounds, and will be followed by the Pro14 Rainbow Cup, a competition featuring the four former South African Super Rugby sides, the Bulls, Lions, Sharks and Stormers.

[9] To ensure a competitive balance, the teams were distributed approximately evenly between the conferences based upon their performance in the previous season.

This represented a reduction from previous years, due to a delayed start and in order to make space for the PRO14 Rainbow Cup to be played following the conclusion of the season, which will introduce former Super Rugby teams into the Pro14 competitions.

However, the organiser has confirmed that no play-off game will be used for European qualification this season and that rankings after round 16 will be used to determine which teams will qualify.

[12] Southern Kings entered liquidation in September 2020 and withdrew from the league, while the Cheetahs did not compete due to the COVID-19 pandemic.