Siófok is a town in Somogy County, Hungary on the southern bank of Lake Balaton. It is the second largest municipality in Somogy County and the seat of Siófok District. It covers an area of about 124.66 km² (48.13 square miles) between Lake Balaton, the Mezoföld and the Outer Somogy-Hills. Lying at the firth of the Sió Channel, it serves as the most important logistic station for goods between Lake Balaton and the River Danube.

The town is Hungary's second most popular holiday destination (right after Budapest) thanks to its 17-kilometre-long (11 miles) coast, over 1,000 hotels, and plenty of bars, restaurants and night clubs. Siófok is one of the richest municipalities of Hungary due to tourism. Hungarians often call the town "the capital of Lake Balaton", as it is the largest town on its shores and acts as the financial, cultural, media, commercial and touristic hub of the northern part of Somogy County and the southern shore of Lake Balaton.