Interliner is an express bus system in the Netherlands. In this country the backbone of public transport is the railroad system, and buses are used complementarily. While most bus lines have many stops and are for small distances, Interliner buses travel longer distances with fewer stops, where one can not go by train, or where travel by train would require a considerable detour.

For example they connect North Holland to the northeast using the Afsluitdijk, connect Rotterdam to three islands in the southwest using a tunnel, two dams and a bridge, serve Drachten (which is not served by a railroad), connect Lelystad to the north through the Noordoostpolder, and Groningen to Emmen.

Uniformity has been abandoned with part of the system being renamed Q-Liner (also called Q-liner and Qliner) and a distinction between grey and green interliner.