The club has announced it will use the space traditionally reserved for player names to display the world 'Barcelona' to commemorate those who lost their lives.
The '#TotsSomBarcelona' hashtag, which translates as 'We Are All Barcelona', will also be emblazoned across the front of the famous first-team shirt for their league opener at Camp Nou.
Thirteen people died and more than 100 were injured when a van drove into pedestrians on the crowded Las Ramblas street, an incident that local police are treating as an act of terrorism.
Five terror suspects were later killed in a police operation in Cambrils, a resort town roughly 100 kilometres from Barcelona, in a second vehicle attack in which one woman died.
Barca officials joined the city's people in observing a minute's silence on Friday and the players will wear black armbands this weekend.
"We would like to show our solidarity with the victims and their families in these difficult times," coach Ernesto Valverde said.
"We are here to help in any way we can."