Spiez is a city in the Frutigen-Niedersimmental administrative district in the canton of Bern in Switzerland.

Spiez has an area of 16.8 km² (6.5 sq mi). Of this area, 38.5% is used for agricultural purposes, while 29.1% is forested. Of the rest of the land, 29.1% is settled (buildings or roads) and the remainder (3.3%) is non-productive (rivers, glaciers or mountains).

It is located at the south bank of Lake Thun. It comprises five villages (Bäuerte): Spiez, Einigen, Hondrich, Faulensee and Spiezwiler (formerly Wyler).

Spiez has a population (as of 31 December 2010) of 12,475. As of 2007^[update], 7.4% of the population was made up of foreign nationals. Over the last 10 years the population has grown at a rate of 6.8%. Most of the population (as of 2000^[update]) speaks German (94.0%), with Serbo-Croatian being second most common (1.1%) and French being third (0.8%).

In the 2007 election the most popular party was the SVP which received 32.9% of the vote. The next three most popular parties were the SPS (21%), the Green Party (12.9%) and the FDP (11.8%).