The artists wrote graffiti reading "Homeland is racist" and "Homeland is rubbish", among others.
They say they were asked to write the graffiti in June to "lend authenticity" to a set depicting a refugee camp.
The episode featuring the set in question aired on 11 October in the US.
It will be broadcast on Sunday in the UK.
Some of the messages were briefly visible in the background of the scenes depicting a Syrian refugee camp in Lebanon.
The artists said in a statement that they were initially reluctant about the commission "until we considered what a moment of intervention could relay about our own and many others' political discontent with the series".
"It was our moment to make our point by subverting the message using the show itself," they said.
They said that no-one working on the show checked what it was that they were actually writing, with the set designers "too frantic to pay any attention to us" and the Arabic script treated as "merely a supplementary visual".
Caram Kapp, one of the artists, told the BBC: "In this graffiti we are trying to call for a more differentiated view of the region, and we're also trying to say that things aren't as simple as they seem on this show."
In the second series of the show, its depiction of the Lebanese capital Beirut sparked criticism with many pointing out that its portrayal of the city's central Hamra Street thoroughfare bore little relation to reality.
Some Pakistani viewers were also irked by the way the Pakistani capital Islamabad was depicted in a later series, as well as the fact that a terrorist character's name was almost identical to that of a previous Pakistani ambassador to the US.
The episode featuring the set in question aired on 11 October in the US. It will be broadcast on Sunday in the UK.

The Australian, whose car has a major aerodynamic update, was 0.234 seconds quicker than Ferrari's Kimi Raikkonen.
Title rivals Lewis Hamilton and Sebastian Vettel were third and sixth, Hamilton 0.7secs quicker than Vettel and 0.372secs behind Ricciardo.
Hamilton, who has won five times in 10 years in Hungary, trails Vettel by one point at the mid-point of the season.
Hamilton was 0.4secs quicker than team-mate Valtteri Bottas, who was fifth behind the second Red Bull of Max Verstappen, and 0.6secs off Ricciardo, struggling with his set-up.
Vettel also appeared to be struggling. The four-time champion was a second off the pace, complained of a lack of rear grip and had a spin and a number of moments when he ran wide and off track.
He was not the only one to fall prey to the slippery surface at the Hungaroring.
Both Haas drivers crashed at the fast Turn 11, Romain Grosjean incurring only light damage, but reserve driver Antonio Giovinazzi bringing out a red flag when he buried his car in the wall, damaging the left-hand side.
And at the end of the session, Renault's Jolyon Palmer lost control at the exit of the fast uphill kink at Turn Four, bouncing over the kerbs and smashing his front wing to pieces.
Palmer finished the session in an encouraging 10th, just one place and 0.3secs behind team-mate Nico Hulkenberg on a weekend when he is under pressure. Former F1 driver Robert Kubica will test with Renault at this track next week as the team assess whether the Pole is capable of returning to the sport more than six years after a horrific rally crash left him with only partial use of his right arm.
It was not immediately clear whether Palmer had damaged the new floor that was introduced for the first time at the last race and which he was using for the first time. Plus, if he had, whether Renault had sufficient spares to fit a new one.
McLaren lived up to their promise to perform better than usual in Hungary because of the relative unimportance of engine power at the track, with Fernando Alonso and Stoffel Vandoorne best of the rest in seventh and eighth places.
Artists hired by the makers of the US show Homeland to write graffiti on one of its sets in Berlin say they wrote messages criticising the show's alleged stereotypes of Arabs and Muslims.
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Red Bull's Daniel Ricciardo sprung a surprise with fastest time in first practice at the Hungarian Grand Prix.