The Muhajir people (also spelled Mohajir and Mahajir) (Urdu: مہاجر) are a multi-origin ethnic group of Pakistan. They are the Muslim immigrants of various ethnic groups and regional origins, who migrated from various regions of India after the 1947 independence to settle in the newly independent state of Pakistan, and their descendants. Muhajirs come from various ethnic and regional backgrounds, with a significant portion of the community residing in Karachi and other major urban centers of Pakistan.

The total population of Muhajrs worldwide is estimated to be around 15 million, and the overwhelming majority of this figure (14.7 million) is located in Pakistan, according to the 2017 Pakistani census. Though the official controversial 2017 census of Karachi, which has historically hosted the country's largest Muhajir population, has been challenged by most of Sindh's political parties.

The Urdu term muhājir (Urdu: مہاجر) comes from the Arabic muhājir (Arabic: مهاجر), meaning an "immigrant", or "emigrant". This term is associated in early Islamic history to the migration of Muslims and connotes 'separation, migration, flight, specifically the flight of the Prophet from Mecca to Medina'. This term was popularised in Pakistan by the 1951 census, although its earliest uses date back to Partition.

Most of the Muhajirs who settled in the Sindh province of Pakistan came from the present-day Indian states of Central Provinces, Berar, Bombay, United Provinces, Haryana, Gujarat, Himachal Pradesh, Bihar and Delhi, while others were from princely states of Jammu and Kashmir, Rajasthan, Hyderabad, Baroda, Kutch, and the Rajputana Agency.

Muhajirs, worldwide, have a population of over 15 million. Urdu-speaking Muhajirs are mostly settled in Pakistan and currently are the fifth-largest ethnic group of Pakistan, with a population of around 7.6% of the national population, according to the census. Although the population figures of the Muhajir dominated city of Karachi, have faced many controversies mainly due to the controversial 2017 census of Pakistan. The population figure has been rejected by most major political parties of Sindh including MQM-P, PSP, and PPP.

Estimates of Muhajir nationalist organizations range from 22 million to around 30 million. Conversely, Christophe Jaffrelot gives a lower number, estimating their modern population to number between 7 and 9 millions, mostly in Karachi. The variation in population estimates arises from differing definitions: the term Muhajir as an ethnic group typically refers to descendants of migrants from present-day India, whereas the broader category of Urdu speakers may also include millions of individuals, particularly ethnic Punjabis in major urban centers, who now speak Urdu as their first language.

Historically, Muhajirs have constituted above 7% population of West Pakistan (3.5% in Pakistan as a whole).

Being a multi-linguistic group of people, the Muhajirs speak different languages natively depending on their ethnicity and ancestral history.