West Sikkim is a district of the Indian state of Sikkim. Its capital is Geyzing, also known as Gyalshing. The district is a favourite with trekkers due to the high elevations. Other important towns include Pelling and Jorethang.

West Sikkim is the site of the ancient state capital Yuksom. It served as Sikkim’s capital beginning in 1642 for almost 50 years until it was shifted to Rabtense. The district was under the occupation of the Nepalese for 30 years in the eighteenth and nineteenth centuries. After Anglo-Nepalese War (1814–16), the district was returned to Sikkim.

West Sikkim covers an area of 1,166 square kilometres (450 sq mi). Attractions include the Khecheopalri Lake, where, according to legend, not a leaf is allowed to fall on the surface of the lake and the Dubdi Monastery, the first monastery of the state.

The economy is mainly agrarian, despite most of the land being unfit for cultivation owing to the precipitous and rocky slopes.

The region has many power projects and enjoys almost uninterrupted electricity. Roads are in poor condition owing to the frequent landslides.

According to the 2011 census West Sikkim district has a population of 136,299, roughly equal to the nation of Grenada.This gives it a ranking of 608th in India (out of a total of 640).The district has a population density of 117 inhabitants per square kilometre (300/sq mi).Its population growth rate over the decade 2001-2011 was 10.58%.West Sikkim has a sex ratio of 941 females for every 1000 males, and a literacy rate of 78.69%.

The district has a wide variety of fauna and flora to offer. Since most of the district is hilly it enjoys a temperate climate. Above 3,800 m (12,000 ft) the slopes are full of rhododendron forests.In 1977 West Sikkim district became home to Khangchendzonga National Park, which has an area of 1,784 km2 (688.8 sq mi).It shares the park with North Sikkim district.