The following is the squad list for the 2017 FIFA U-20 World Cup. Each squad consisted of 21 players in total, three of whom had to be goalkeepers.
Players name marked in bold have been capped at full international level.
Group A
South Korea
Head coach: Shin Tae-yong
Guinea
Head coach: Mandiou Diallo
Argentina
Head coach: Claudio Úbeda
England
On 19 May, Ezri Konsa replaced injured Rico Henry.
Head coach: Paul Simpson
Group B
Venezuela
Head coach: Rafael Dudamel
Germany
Head coach: Guido Streichsbier
Vanuatu
Head coach: Dejan Gluščević
Mexico
Head coach: Marco Antonio Ruiz
Group C
Zambia
Head coach: Beston Chambeshi
Portugal
On 2 May 2017, Portugal announced their 21-man final list. On 9 May, Hélder Ferreira replaced the injured Aurélio Buta.
Head coach: Emílio Peixe
Iran
Head coach: Amir Hossein Peiravani
Costa Rica
Head coach: Marcelo Herrera
Group D
South Africa
On 17 May, Sirgio Kammies replaced the injured Phakamani Mahlambi.
Head Coach: Thabo Senong
Japan
Head coach: Atsushi Uchiyama
Italy
Head coach: Alberigo Evani
Uruguay
Head coach: Fabián Coito
Group E
France
On 21 May, Faitout Maouassa replaced injured Ronaël Pierre-Gabriel.
Head coach: Ludovic Batelli
Honduras
Head coach: Carlos Tábora
Vietnam
Head coach: Hoàng Anh Tuấn
New Zealand
Head coach: Darren Bazeley
Group F
Ecuador
Head coach: Javier Rodríguez
United States
On 17 May, Auston Trusty replaced the injured Marlon Fossey.