They're in the Netherlands to face A-Z Alkmaar, who currently sit fourth in the Eredivisie.
Dundalk boss Stephen Kenny says getting to this point in their history has been a while in the making.
Kick-off is at 6.
The other game in Group D kicks off at the same time and sees Macabbi Tel Aviv play host to Zenit St. Petersburg.
Manchester United manager Jose Mourinho is resting Wayne Rooney for their Group A opener with Feyenoord.
While Southampton open their Group K campaign at home to Sparta Prague.
It's been confirmed that the 2018 Champions League final will be played in Kiev's Olympic Stadium.
Meanwhile, Tallinn will host 2018's Europa League decider.
