The 19-year-old has been a regular for Blues under-23s this season, where he has made 15 appearances and scored one goal.
Boyd-Munce has previously represented Northern Ireland Under-19s, but this is first call-up to the next age group.
Born in Belfast, he joined Blues as a scholar in 2016.
During their one-week camp in Marbella, Ian Baraclough's Northern Ireland youngsters will play two friendlies against Bulgaria (22 March) and Mexico (25 March).
The full 20-man Northern Ireland Under-21s squad is as follows:
Goalkeepers – Declan Dunne (Portadown, on loan from Cliftonville), Jared Thompson (Warrenpoint Town, on loan from Chelsea).
Defenders – Eoin Toal (Derry City), Pierce Bird (Notts County), Kofi Balmer (Ballymena United), Daniel Finlayson (Rangers), Bobby Burns (Hearts), Danny Amos (Hartlepool, on loan from Doncaster Rovers), Nathan Kerr (Glentoran).
Midfielders – Alfie McCalmont (Leeds United), Jake Dunwoody (Stoke City), Kyle McClean (Linfield, on loan from St Johnstone), Cameron Palmer (Rangers), Ethan Galbraith (Manchester United), Liam Coyle (Liverpool), Caolan Boyd-Munce (Birmingham City).
Forwards – Shayne Lavery (Falkirk, on loan from Everton), David Parkhouse (Derry City, on loan from Sheffield United), Josh Kelly (Maidenhead United), Chris Gallagher (Glentoran).