Lys (French pronunciation: [lis]; Occitan: Lo Lis) is a commune in the Pyrénées-Atlantiques department in southwestern France.

The river Landistou [fr], a 12.5 km long tributary of the Béez, passes through the village Lys. Several tributaries of the Landistou (Betbeder, Bonnasserre, Chourrup, Lazerau, Lespereu) also pass through the commune. The northern part of the commune is drained by the river Luz [fr], a 15.2 km long tributary of the Gave de Pau, and some of its tributaries (Gest, Herran, Luz de Casalis). The southern part of the commune is drained by the stream Ruisseau de la Fontaine de Mesplé (Béez basin), and its tributary Ruisseau de Subercase.

• lou Boscq
• Vic de Hoges de Baix
• Vic de Hoges de Haut
• Vic de Lis de Baix
• Vic de Lis de Haut

• Sévignacq-Meyracq to the north
• Haut-de-Bosdarros to the northeast
• Bruges-Capbis-Mifaget to the east
• Sainte-Colome to the southwest
• Louvie-Juzon to the south

The name Lys appears as Lis-Sainte-Colomme (Lily Saint Colomme) from the 1721 census. The name comes from Gascony, and means 'flat land'.

Lys was formerly an annex of Sainte-Colome until it acquired municipality status in 1858.

The current mayor is Nadège Poueymirou Bouchet, in office since 2020.

The town is part of the following intercommunal structures:

• Communauté de communes de la Vallée d'Ossau (Ossau Valley)
• Syndicat de la perception d'Arudy
• SIVU d'assainissement (sanitation) de la vallée d'Ossau
• Ossau Valley water union
• Lower Ossau electric union

Historical population

Year Pop. ±% p.a. 1861 1,080 —     1866 1,070 −0.19% 1872 1,084 +0.22% 1876 1,040 −1.03% 1881 962 −1.55% 1886 985 +0.47% 1891 998 +0.26% 1896 924 −1.53% 1901 916 −0.17% 1906 908 −0.18% 1911 856 −1.17% 1921 685 −2.20% 1926 657 −0.83%	Year Pop. ±% p.a. 1931 622 −1.09% 1936 621 −0.03% 1946 564 −0.96% 1954 526 −0.87% 1962 518 −0.19% 1968 450 −2.32% 1975 430 −0.65% 1982 412 −0.61% 1990 376 −1.14% 1999 348 −0.86% 2007 354 +0.21% 2012 350 −0.23% 2017 334 −0.93%
Source: EHESS and INSEE (1968-2017)

The town's economy is primarily oriented toward agriculture and livestock (sheep, cattle, pigs, mules).

• Ossau Valley
• Communes of the Pyrénées-Atlantiques department
• Sainte-Colome