Anelka left the club after just two years, joining Real Madrid for £22.3million which many fans believed paid for the Gunners' new training ground in London Colney.
"We all know he terrorised teams when he first arrived in England," Henry said on Sky Sports.
“Listen, for me people do not mention him as they should mention him.
“He was one of the best strikers we have seen in this league.
“Listen, he won it at Arsenal at a young age in that league where it was very difficult. You had to battle away from home all the time. He was young and he did it. He did it at Chelsea, he won the league there, top goalscorer there.
“I think, obviously we all know the story where he left to go to Real Madrid, but we're talking about one of the best strikers we have seen in this league.
“I think he was pivotal to that squad obviously."