The Chilean, who has three caps for his country, signed for United from Universidad in his homeland two years ago.
He failed to make an impact at Old Trafford, however, and is yet to make an appearance for the first team.
After a brief loan spell to Wigan Athletic during the 2012-13 season, the 20-year-old spent last term in Spain with Segunda Division outfit Real Zaragoza, scoring six times in 25 appearances.
Currently leading the Croatian top flight with a perfect record after four matches, Zagreb face Petrolul Ploiesti in the first leg of their UEFA Europa League play-off clash a week on Wednesday.
And Henriquez is thrilled at the prospect of helping his new side reach the first round proper.
"I'm happy with my arrival at Dinamo and I want to do good things," he told the club's official website.
"I have a lot of motivation and I want to prove myself, and I believe that Dinamo is a great club for it.
"I want to help the club enter the group stages of the Europa League, and then make the right result."
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