Both players have recently been representing England. The Three Lions came up against Ivory Coast at Wembley Stadium in a friendly earlier this week.
Before and during the match, some England fans booed Maguire, which Henderson was not a fan of.
The 31-year-old wrote the following on Twitter: "I can’t get my head around what happened at Wembley tonight. Harry Maguire has been a colossus for England.
"Without him, the progress made at the last two tournaments (2018 World Cup semi-finals and 2020 Euros final) would not have been possible. To be booed at his home stadium, for no reason?
"What have we become? What happened tonight was just wrong. As someone who wants to win with England I feel fortunate to share a dressing room with him.
"We all feel the same."
Anfield Watch Verdict
Yes, Maguire is a Manchester United player. But, no one should have an issue with Henderson supporting a human being.
The reality is, there is still a human element to football. Maguire has struggled this season. The 29-year-old has been copping it from some Manchester United fans for his performances.
Maguire has now been booed by a section of England supporters. We can't imagine that he would be feeling too good about himself at the moment.
Henderson's support of Maguire highlights why he is the captain of Liverpool. The man is simply a brilliant leader.
Liverpool did defeat Manchester United 5-0 at Old Trafford earlier this season. So, we are expecting Jurgen Klopp's side to get the business done again.