1965–66 Eerste Divisie

The Dutch Eerste Divisie in the 1965–66 season was contested by 15 teams, one less than in the previous year. This was due to the merger of Enschedese Boys with eredivisie-club SC Enschede, to form FC Twente. Sittardia won the championship.

New entrants
Promoted from the 1964–65 Tweede Divisie: Relegated from the 1964–65 Eredivisie:
 * SC Cambuur
 * Xerxes
 * NAC Breda
 * Sittardia

League standings
Due to the expansion of the eredivisie to eighteen teams, and the expansion of this division to twenty teams next year, more teams were promoted and only one team relegated this year.