The 2018 Copa do Brasil third stage was the third stage of the 2018 Copa do Brasil football competition. It was played from 28 February to 15 March 2018. A total of 20 teams competed in the third stage to decide ten places in the fourth stage of the 2018 Copa do Brasil.
In the third stage, each tie was played on a home-and-away two-legged basis. If tied on aggregate, the away goals rule would not be used, extra time would not be played and the penalty shoot-out would be used to determine the winner. Host teams were settled in a draw held on 21 February 2018, 11:00 at CBF headquarters in Rio de Janeiro.
|Team 1||Agg.||Team 2||1st leg||2nd leg|
|Atlético Paranaense||1–1 (6–5 p)||Ceará||0–0||1–1|
|Ponte Preta||0–0 (5–3 p)||Sampaio Corrêa||0–0||0–0|
|Figueirense||2–2 (2–4 p)||Atlético Mineiro||0–1||2–1|
|Felipe Azevedo 33'||Report||Guilherme 14'|
Tied 1–1 on aggregate, Atlético Paranaense won on penalties and advanced to the fourth round.
Internacional won 4–0 on aggregate and advanced to the fourth round.
|Ibañez 10'||Report||André Moritz 43'
Avaí won 3–1 on aggregate and advanced to the fourth round.
|Wilson 50' (pen.)||Report||Carlos Eduardo 29'|
Goiás won 2–1 on aggregate and advanced to the fourth round.
|Ponte Preta||0–0||Sampaio Corrêa|
|Sampaio Corrêa||0–0||Ponte Preta|
Tied 0–0 on aggregate, Ponte Preta won on penalties and advanced to the fourth round.
Éder Militão 41'
|Report||Marcos Guilherme 5'
Rodrigo Caio 58'
São Paulo won 5–0 on aggregate and advanced to the fourth round.
|Matheus Peixoto 38'||Report|
|Neílton 21', 63', 72'||Report|
Vitória won 3–1 on aggregate and advanced to the fourth round.
|Ricardo Oliveira 25'||Report||Zé Antônio 21'
Jorge Henrique 70'
|4–2|| Jorge Henrique
Tied 2–2 on aggregate, Atlético Mineiro won on penalties and advanced to the fourth round.
|Janeudo 45+3' (pen.)||Report||Keké 75'|
Ferroviário won 2–1 on aggregate and advanced to the fourth round.
Náutico won 3–1 on aggregate and advanced to the fourth round.
- "COPA DO BRASIL - TABELA BÁSICA / EDIÇÃO 2018" (PDF) (in Portuguese). CBF.
- "Regulamento Específico da Competição Copa do Brasil 2018" (PDF) (in Portuguese). CBF.
- "Copa do Brasil: mandos de campo da Terceira Fase" (in Portuguese). CBF. 21 February 2018.
- "Sem laudos da Arena Pantanal, Cuiabá x Náutico será de portões fechados" (in Portuguese). Globo. 12 March 2018.