The club announced Ernesto Valverde's team will wear black armbands at their Spanish league opener against Real Betis on Sunday - as will all other La Liga clubs - and will also hold a minute's silence at the game.
Barcelona observing a minute of silence for the victims of the crash before their training session.
The loss at the Santiago Bernabeu sealed a 5-1 aggregate win for Real, prompting defender Gerard Pique to remark that he felt inferior to Madrid for the first time in a decade.
The starting players will have the city's name "Barcelona" in place of their names on the backs of the jerseys, and the front of the shirts will be embroidered with the hashtag TotsSomBarcelona (We are all Barcelona).
FC Barcelona have led tributes to those killed and injured in the terrorist attacks in the Catalan city on Thursday.
"The club wishes to send our support and thoughts to the victims, their families and friends as well as the people of Barcelona and its visitors", the club said in a statement.
Barcelona v Real Betis Preview
Barcelona-based Sport's headline went with a take on FC Barcelona's team motto: "Tots units fem forca" (together we are stronger).
"They are extraordinary and lamentable circumstances", said Valverde on Saturday.
Fans in the Barca singing section borrowed a line from the club's anthem in a banner that read: "No one can ever break us", whilst chants of "we are not afraid" rang out after the minute's silence. "We have to do our best in the circumstances and the best way [to do that] is to continue forward". What we can not do is hide. It was a very tough day for everyone and it gives you reasons to think'.
Barca have struggled for form in recent weeks, losing comprehensively to Real Madrid in the Spanish Super Cup prior to the resumption of La Liga.
"We would like to show our solidarity with the victims and their families in these hard times. These things put all the small problems we face in our lives everyday into perspective".
Messi added on Instagram: "I would like to send my condolences and all my support to the families and friends of the victims of the bad attack on our beloved Barcelona, as well as totally reject any act of violence". PSG signed a world-record transfer fee of US$250 million to get Neymar, and he played his first game with them last weekend (scoring a pretty goal).