Both sets of fans are unhappy with the ownership of their clubs
The latest protest by Charlton fans has seen plastic pigs thrown onto the pitch during their League One game with Coventry.
Some supporters are unhappy about the club's ownership under Roland Duchâtelet, and this isn't the first time one of their matches has had to be halted.
Up to 3,000 of the plastic pigs ended up on the pitch after a minute of play leading to a five minute delay.
Coventry fans, some of whom are unhappy with how their club is being run by Sisu, also got involved in the protest.
Charlton last played in the Premier League back in 2006-07 after a seven-year stay in the top flight under the management of Alan Curbishley.
They have since oscillated between the Championship and League One.
They spent three seasons in the third tier between 2009 and 2012 before being relegated again from the second tier at the end of last season after a 22nd place finish in the Championship.
After 34 years in the top flight, Coventry City were relegated from the Premier League in 2001 and were relegated to the third tier for the first time in almost half a century in 2012.
Video via The Mirror: