The Carabao Cup final between Tottenham and Manchester City will have 8,000 fans in attendance after it was confirmed as a pilot event by the UK government to test the return of large crowds.
A proportion of the tickets will be available to both finalists.
The English Football League (EFL), who organise the League Cup, says ticket information will be made available at a later date.
Doctor who saved Newcastle fan hailed as hero by Toon fans
- Man Utd set to pay off De Gea's huge contract - Paper Round
- Alexander-Arnold display against Arsenal shows he must go to Euro 2020
EFL chairman Rick Parry said: "The Carabao Cup is a prized asset of the EFL, a great competition for clubs to win and always a fantastic occasion so we are absolutely delighted to see supporters back for the 2021 final, in what will hopefully be another important milestone along the way to a full return of fans.
"Football has lots of expertise in crowd management so we welcome the opportunity to support the Government in its Events Research Programme and will also take great pride in hosting NHS staff at the final to whom we owe so much for their momentous efforts throughout the pandemic."
The trial, to be run at nine events including the FA Cup final and one semi-final, will be used to assess whether large events can be held in closed settings without social distancing.
The FA Cup semi-final between Leicester City and Southampton on April 18 will be allowed to host an audience of 4,000, while a crowd of 21,000 will be permitted for the final on May 15. Both matches will be held at Wembley.
Barcelona line-up Serie A duo as Haaland alternatives - Euro Papers
Jarring scenes at Newcastle, is Solskjaer finished? - The Warm-Up
Nuno happy with Tottenham's 'amazing job' in win over Newcastle