The Dutch midfielder will move to the John Smith's Stadium on a three-year contract with the option of an extra year at the end of the 2020-21 season.
The 20-year-old, who has made over 80 appearances in the Erevidisie, has featured in the Europa League and with the Netherlands' Under-21 team.
"I'm delighted that we've been able to bring Juninho in, especially before we report back as it allows him to have a full pre-season with the team," Huddersfield coach David Wagner told the club's official website.
"He's a young, hungry player that has already played a lot of football for someone of his age and even if he's still very young, he strengthens our options in this position after we lost Dean Whitehead to retirement at the end of last season.
"He's an exciting midfielder that offers all the aggression of a defensive midfielder and the technical skills and mobility of an offensive midfielder. We will give him all the support he needs to make the best out of the potential he definitely has."
Huddersfield begin their Premier League campaign with a trip to Stamford Bridge to face Chelsea.