The 35-year-old former PSG hero moved to Old Trafford on a free transfer in the 2016 summer window - the contract he signed did have a clause that could see him extend his one-year deal to a two-year one.
In his 17 appearances for United this year, he has managed to score eight goals, which pales in comparison to the heights he has become used to but is still a decent return for his first handful of games in the Premier League.
In a press conference this week, Mourinho said: "We are going to execute the option of a second season.
After that he can do what he wants."
Zlatan's future at Man U sealed
Zlatan, who managed to tot up 62 goals in 116 games for Sweden before his retirement following their Euro 2016 exit, left French Champions PSG at the end of last season.
He became a modern legend for Paris Saint-Germain during his four years there. He managed 156 goals in 180 games for the French giants, winning 12 major honours along the way - including four Ligue 1 titles.
This is not unusual for Ibra though as he has won a major trophy every year since 2001 - made even more impressive when you consider he has played for seven different clubs in that time.
He will have a statue erected in Stockholm in his honour after being named Sweden's top player for a 10th successive year on Monday.
Speaking on whether he'd be up for another year at Old Trafford, Zlatan said: "I feel in shape, feel fresh and good. If I feel like I do now, it will be a second year."
Going forward
The majority of Red Devils' supporters will be thrilled to hear Ibrahimovic would be happy to stay at their club for another year but with players like Anthony Martial going well under the radar, could it really be considered a good move for the club?
Martial has made just seven appearances for United in the Premier League this season (so far) and has only been able to score a single goal, presumably because he's unable to gather any sort of momentum.
If the French wonder-kid stays at United, and Zlatan signs for another year, he will be 23 years old and while that's still very young to be playing for a club like Manchester United, he'd have to go out on loan to continue his rapid development.
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