Piz Buin

Infobox Mountain
Name = Piz Buin
Photo = Piz_Buin_vom_Ochsentaler_Gletscher_HQ.jpg
Caption = View from Ochsentaler Glacier, July 2001
Elevation = convert|3312|m|ft|0
Location = AUT / SUI
Range=Silvretta
Prominence = convert|537|m|ft|0
latd= 46|latm=50 |lats=44 |latNS=N
longd=10 |longm=7 |longs=11 |longEW=E
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Coordinates = coord|46|50|44|N|10|7|11|E|type:mountain_region:CH/AT|display=inline,title
Topographic
Type=| Age=
First ascent = 1865 by I.A. Specht and J. Weilenmann| Easiest route = glacier/snow climb

Piz Buin is one of the highest mountains in the Silvretta mountain range, between Austria and Switzerland. The tallest mountain is Piz Linard at 3,410m (11,188 ft). It forms the border between Graubünden and Vorarlberg and is the highest mountain peak in Vorarlberg.

Its original name in the Romansh language is "Piz Buin Grand". A similar but smaller summit nearby is called "Piz Buin Pitschen" at 3,255m (10,680 ft).

Piz Buin can be reached from the Wiesbadener hut in Austria, crossing the Vermunt glacier, climbing up the Wiesbadener ridge and hiking over the Ochsentaler Glacier to the Buin gap. From the gap there is a zigzag walk to the top, with only a 20 m (65 ft) steep step to surmount before reaching the relatively flat summit space, which has an old wooden cross on the very top. The border between Switzerland and Austria crosses the summit from East to West.

"Piz Buin" is also a trading name of a suncream firm, which is headquartered in Vorarlberg and is well known all over the worldFact|date=July 2008.