The Furka Base Tunnel is a 15.4 kilometer long Swiss rail tunnel that connects Oberwald (at 1369 metres above sea level) in the Canton of Valais with Realp (at 1538 m) in the Canton of Uri. The tunnel replaced the previous overland track that climbed to an apex of 2160 metres above sea level at the Furka stop below Furka Pass (2431 m). The old line has partly been reopened by the Furka Heritage Railway for touristic trains which pass the Furka Pass via the 1,8 km Furka Tunnel.

The tunnel allows the Matterhorn-Gotthard train to provide year-round service to its entire network. Previously, the overland route closed during the winter months because of heavy snowfall and large sections of the overhead electrical lines had to be dismantled. In 1976, the Parliament of Switzerland passed a bill for its construction, sponsored by Roger Bonvin, following an initial cost estimate of 76 million francs.

The construction costs quickly escalated due to the difficult geological conditions and, in the end, exceeded 300 million Francs. The political fighting surrounding the cost overruns are said to have contributed to Roger Bonvin's ill health toward the end of the project and he died during its opening in 1982.

In its initial year of operation, the tunnel was used to transport more than 75,000 passenger cars, trucks and buses. Currently, it also serves both an hourly regional train and 10 daily Glacier Express trains between Zermatt and the ski resort town of St. Moritz. During the winter skiing season, traffic in the tunnel consistently approaches maximum capacity.

A plaque commemorating Roger Bonvin is installed as the tunnel's entrance in Oberwald.

Coordinates: 46°32′7″N 8°27′12″E / 46.53528°N 8.45333°E / 46.53528; 8.45333