The 2020 Campeonato Paulista Série A3 is the 27th season of the third level of the São Paulo state league under its current title and the 67th season overall.

Due to the ongoing COVID-19 pandemic, the season was indefinitely suspended on 16 March.

[7] Velo Clube were crowned champions, winning promotion alongside EC São Bernardo.

The following teams have changed division since the 2019 season.

Promoted from Segunda Divisão Relegated from Série A2 Promoted to Série A2 Relegated to Segunda Divisão Ivan Canela (caretakers) Ivan Canela (caretakers)