Arshavin struggled to nail down a regular starting berth last season, making 11 appearances. Squillaci featured just once while Denilson has spent the last two campaigns on loan at Sao Paulo.
Arsenal said in a statement: "Andrey Arshavin, Denilson and Sebastien Squillaci will leave the club when they come to the end of their contracts on June 30, and Arsenal would like to take this opportunity to thank them for their contribution and wish them well for the future."
Russia international Arshavin joined the Gunners from Zenit St Petersburg for £15million on the final day of the 2009 January transfer window, and went on to score 31 goals in 144 appearances.
The 32-year-old famously netted four times in the 4-4 draw at Liverpool in April 2009, and represented Russia at Euro 2008 and 2012.
Denilson made 153 appearances over five years at the club and featured in all but one Premier League game during the 2008-09 season.
Squillaci signed from Sevilla in 2010 and was a regular during his first season at the club. However, the French international has made just seven appearances in the past two campaigns.