Janssen played for the first time for a Junior selection of Royal Dutch Football Association on 17 March 2010 at the friendly match of U-15 national team against England. In 2012, she was captain of the Dutch U-17 team in the qualifying matches for the 2012 UEFA Women's Under-17 Championship and also led the team, as captain, in qualifying for the 2013 UEFA Women's Under-19 Championship. In 2014, she succeeded with her team to qualify for the final round the 2014 UEFA Women's Under-19 Championship in Norway, where Netherlands won the title for the first time with 1–0 victory against Spain. Janssen played all five matches in the tournament.