The 2020 Davis Cup World Group I was held on 5–6 March 2021 and 17–19 September 2021.
The eight highest-ranked winners of the World Group I ties automatically progressed to the 2022 Davis Cup qualifying round.
The four lowest-ranked winners took part in an additional knock-out tie in November 2021, the two winners progressing to the 2022 Davis Cup qualifying round and the two losers contesting the 2022 Davis Cup World Group I play-offs.
[1] Twenty-four teams participated in the World Group I, in a series decided on a home and away basis.
[2] These twenty-four teams were: The eight highest-ranked (as at 20 September 2021) winners of the World Group I ties automatically progressed to the 2022 qualifiers.