Aloys I, Prince of Liechtenstein (born Aloys Josef Johannes Nepomuk Melchior) was the Prince of Liechtenstein from 1781 until his death. He was the third son of Franz Josef I.
Aloys was enlisted in the military as a youth but withdrew due to poor health. His great interest was forestry and gardening and had many trees from overseas planted around his manors for both economic and aesthetic reasons. He also decorated Eisgrub Park with ornamental buildings. Aloys I supported mining operations within his lands in Moravia in order to raise money. This included the construction of an ironworks at Olomouc.
Aloys I also expanded the Liechtenstein library through the purchase of complete collections of books. Aloys I had the architect Joseph Hardtmuth design a new palace in Herrengasse, Vienna. He hired a seasonal theater group and a permanent music group.
During his reign, Liechtenstein carried out the last execution in its history when Barbara Erni was beheaded in Eschen for theft.
He was the 836th Knight of the Order of the Golden Fleece in Austria.
Aloys married Karoline Gräfin von Manderscheid-Blankenheim in Feldsberg on 15 November/16 November 1783. The couple was childless, and Liechtenstein went to Aloys' brother Johann I.