Grüningen is a town and municipality in the district of Hinwil in the canton of Zürich in Switzerland, notable for its well-preserved historic nucleus.

Grüningen castle was built from the early 13th century, most likely by the counts of Rapperswil, who acted as reeves for Einsiedeln Abbey.

Around 1230, Grüningen passed from Einsiedeln to the Abbey of Saint Gall and was at first given as a fief to the counts of Kyburg, and in 1253 to Lütold VI, head of the baronial Regensberg family.

The small settlement that had grown up around the castle was developed into a medieval city, with fortifications and market rights, around the mid 13th century, likely under Lütold VI.

The town remained in Habsburg possession throughout the 14th century, administered by the counts of Toggenburg from 1314, and by Heinrich Gessler of Meienberg from 1374.

Gessler improved the castle fortifications against the threat of the Swiss Confederacy in the years leading up to the Sempach War, and Grüningen was raided several times by Zürich during the 1370s to 1380s.

Heinrich Gessler died in 1403 and was succeeded by his son Hermann, who was finally forced to cede Grüningen to Zürich.

Frederick IV of Habsburg was upset over the loss of the territory, and made several attempts to regain Grüningen from Zürich, but ultimately without success.

The defenders surrendered on 10 November 1440, three weeks before Zürich was forced to sign the unfavourable peace of Lucerne, on 1 December 1440.

Frederick V of Habsburg and III of Germany at this time requested the return of Grüningen to Habsburg, but the intercession of Bern, in the so-called Berner Spruch of 17 March 1441, prevented the loss of Grüningen (which would have left a Habsburg-owned enclave within the Swiss Confederacy after the re-admission of Zürich in 1450).

The attackers killed Zürich reeve Peter Kilchmann in spite of having offered safe conduct.

Of the rest of the land, 14.6% is settled (buildings or roads) and the remainder (2.5%) is non-productive (rivers, glaciers or mountains).

[8] The municipality is located in the Zürcher Oberland and includes the town of Grüningen proper, besides the villages and hamlets of Itzikon, Binzikon, Bächelsrüti, Adeltshausen and Holzhausen as well as scattered individual houses.

The Wakker prize was awarded to Grüningen for the efforts that the Heimatschutzgesellschaft (Swiss heritage society) put into maintaining the historic appearance of the town.

They developed and staffed a local museum, presented cultural events and published information about the town's heritage.