Midfielders Isco of Real Madrid and Atletico's Saul Niguez were left out.
Juanfran, who missed the crucial penalty in Saturday's Champions League final shootout, made the cut along with the his Atletico team-mate Koke and Real Madrid winger Lucas Vazquez.
Manchester United goalkeeper David de Gea and Manchester City's David Silva are both in Vicente del Bosque's squad.
Spain, who won the tournament in 2008 and 2012, are in Group D alongside the Czech Republic, Turkey and Croatia.
Goalkeepers: Iker Casillas (Porto), David de Gea (Man United), Sergio Rico (Sevilla)
Defenders: Gerard Pique, Jordi Alba, Marc Bartra (all Barcelona), Cesar Azpilicueta (Chelsea), Mikel San Jose (Athletic Bilbao), Hector Bellerin (Arsenal)
Midfielders: Bruno (Villarreal), Sergio Busquets, Andres Iniesta (both Barcelona), Thiago (Bayern Munich), David Silva (Manchester City), Pedro, Cesc Fabregas (both Chelsea)
Forwards: Aritz Aduriz (Athletic Bilbao), Nolito (Celta Vigo), Alvaro Morata (Juventus)