The Linguistic Survey of India (LSI) is a comprehensive survey of the languages of British India, describing 364 languages and dialects. The Survey was first proposed by George Abraham Grierson, a member of the Indian Civil Service and a linguist who attended the Seventh International Oriental Congress held at Vienna in September 1886. He made a proposal of the linguistic survey and it was initially turned down by the Government of India. After persisting and demonstrating that it could be done using the existing network of government officials at a reasonable cost, it was approved in 1891. It was however formally begun only in 1894 and the survey continued for thirty years with the last of the results being published in 1928.

Sir George Abraham Grierson was an Irish administrator and linguist in British India. He worked in the Indian Civil Service but an interest in philology and linguistics led him to pursue studies in the languages and folklore of India during his postings in Bengal and Bihar. He published numerous studies in the journals of learned societies and wrote several books during his administrative career but proposed a formal linguistic survey at the Oriental Congress in 1886 at Vienna. The Congress recommended the idea to the British Government and he was appointed superintendent of the newly created Linguistic Survey of India in 1898. He continued the work until 1928, surveying people across the British Indian territory, documenting spoken languages, recording voices, written forms and was responsible in documenting information on 179 languages, defined by him through a test of mutual unintelligibility, and 544 dialects which he placed in five language families. He published the findings of the Linguistic Survey in a series that consisted of 19 volumes.