Unteriberg is a village and municipality in Schwyz District in the canton of Schwyz in Switzerland. Besides the village of Unteriberg, the municipality includes the villages of Studen, Waag, Stöcken and Herti.
Unteriberg is first mentioned around 1217-22 as Yberge. Until the separation, in 1884, into Unteriberg and Oberiberg the independent municipality was known simply as Iberg.
Unteriberg is the hometown of noted ski racer Wendy Holdener.
The municipality of Unteriberg lies in the valleys of the Sihl, Waag and Minster rivers, at the southern end of the artificial Sihlsee. The villages of Unteriberg, Stöcken and Herti all lie on the Minster river close to its confluence with the Waag. The village of Waag is on its namesake river, whilst Studen is on the Sihl. To the south of the municipality is the mountain of Druesberg, whose northern slopes are shared between Unteriberg and the neighbouring municipality of Oberiberg. To the east is the Fluebrig mountain.
The municipality has an area, , of . Of this area, 44.4% is used for agricultural purposes, while 35.1% is forested. Of the rest of the land, 2.9% is settled (buildings or roads) and the remainder (17.6%) is non-productive (rivers, glaciers or mountains).
Unteriberg has a population (as of ) of . , 5.4% of the population was made up of foreign nationals. Over the last 10 years the population has grown at a rate of 4.7%. Most of the population () speaks German (98.2%), with Portuguese being second most common ( 0.4%) and Albanian being third ( 0.3%).
the gender distribution of the population was 50.6% male and 49.4% female. The age distribution, , in Unteriberg is; 708 people or 31.9% of the population is between 0 and 19. 638 people or 28.7% are 20 to 39, and 628 people or 28.3% are 40 to 64. The senior population distribution is 151 people or 6.8% are 65 to 74. There are 72 people or 3.2% who are 70 to 79 and 23 people or 1.04% of the population who are over 80.
there are 802 households, of which 194 households (or about 24.2%) contain only a single individual.