The Challenger Pro League, previously known as 1B Pro League is the second-highest division in the Belgian football league system, one level below the Belgian Pro League. It was created by the Royal Belgian Football Association in 2016, replacing the Belgian Second Division. From the season 2016–17 until 2019–20, the competition was named Proximus League, after the main sponsor Proximus.
The Belgian First Division B was created in 2016 as the successor of the Belgian Second Division following an overhaul of the Belgian football league system which saw the number of professional clubs reduced to 24 and the number of teams at the second level of the football pyramid to 8.
During Belgian Second Division era from 1973 to 2016, the second division winner and the play-off winner promote to the first division. From 2016 on, the second division winner is no longer guaranteed promotion. The league is divided in two periods of 15 games. The winners of a period compete each other in a final. If a team wins both periods, no final is played and it automatically rises to the highest level. In 2017, Lierse became champion of the league, but no promotion was allowed because they did not win a period. Antwerp and SV Roeselare played the final.