The arrival of Green will help plug the gap following the departures of Brad Potts and George Moncur and provide the Reds with a valuable fresh option in midfield.
Green has signed a two-and-a-year half year deal with a further option in Barnsley's favour.
Chief executive officer Gautier Ganaye said: “Jordan is an excellent signing for the club. Having spoken at length with Daniel (Stendel) about this position, we knew what we wanted to add.
Jordan brings a huge amount of pace and has a direct view on football where he wants to attack and beat his defender to get to the box.
"This adds competition for places with Jordan, as he is coming here hungry to make his way to the starting XI."
London-born Green, who turns 24 in February, began his career in Fulham's academy before moving into non-league circles with Banbury United where his form attracted the attention of Bournemouth.
Green ended a one-year contract with the Cherries after a successful trial, but could not make a first-team breakthrough at the Vitality Stadium and joined Yeovil in August 2017.
Green's form earned him a contract extension in January 2018, with his form having helped the Somerset club reach the fourth round of the FA Cup and a dream tie with Manchester United.
The diminutive 5ft 6in wingman, who had loan spells at Newport County and Leyton Orient, has freatured 21 times for the Glovers this season, scoring four goals.
He netted Yeovil's winner in his final appearance for the club last weekend in a 1-0 victory at Mansfield Town.