Newar (/nɪˈwɑːr/; Newar: नेवार, endonym: Newa; Newar: नेवा, Pracalit script: 𑐣𑐾𑐰𑐵𑑅‎), or Nepami, are primarily inhabitants in Kathmandu Valley of Nepal and its surrounding areas, and the creators of its historic heritage and civilisation. Newars are a distinct linguistic and cultural group, primarily Indo-Aryan and Tibeto-Burman ethnicities, who share a common language, Nepal Bhasa, and predominantly practice Newar Hinduism and Newar Buddhism. Newars have developed a division of labour and a sophisticated urban civilisation not seen elsewhere in the Himalayan foothills. Newars have continued their age-old traditions and practices and pride themselves as the true custodians of the religion, culture and civilisation of Nepal. Newars are known for their contributions to culture, art and literature, trade, agriculture and cuisine. Today, they consistently rank as the most economically and socially advanced community in Nepal, according to the annual Human Development Index published by UNDP. Newars are ranked the 8th largest ethnic group in Nepal according to the 2021 Nepal census numbering 1,341,363 people constituting 4.6% of the total population.

The Kathmandu Valley and surrounding territories constituted the former Newar kingdom of the Nepal Mandala. Unlike other common-origin ethnic or caste groups in Nepal, the Newars are regarded as an example of a nation community with a relict identity, derived from an ethnically diverse, previously existing polity. The Newar community within it consists of various strands of ethnic, racial, caste and religious heterogeneity, as they are the descendants of the diverse group of people that have lived in Nepal Mandala since prehistoric times. Indo-Aryan tribes like Maithils of Madhesh Province, the Licchavis, Kosala, and Mallas (N) from respective Indian Mahajanapada (i.e. Licchavis of Vajji, Kosala, and Malla (I)) that arrived at different periods eventually merged with the local native population by marriage as well as adopting their language and customs. These tribes however retained their Vedic culture and brought with them their Sanskritic languages, social structure, Hindu religion and culture, which were assimilated with local cultures and gave rise to the current Newar civilisation. Newar rule in Nepal Mandala ended with its conquest by the Gorkha Kingdom in 1768.

The terms "Nepāl", "Newār", "Newāl" and "Nepār" are phonetically different forms of the same word, and instances of the various forms appear in texts in different times in history. Nepal is the literary (Sanskrit) form and Newar is the colloquial (Prakrit) form. A Sanskrit inscription dated to 512 in Tistung, a valley to the west of Kathmandu, contains the phrase "greetings to the Nepals" indicating that the term "Nepal" was used to refer to both the country and the people.

The term "Newar" or "Newa:" referring to "inhabitant of Nepal" appeared for the first time in an inscription dated 1654 in Kathmandu. Italian Jesuit priest Ippolito Desideri (1684–1733) who traveled to Nepal in 1721 has written that the natives of Nepal are called Newars. It has been suggested that "Nepal" may be a sanskritization of "Newar", or "Newar" may be a later form of "Nepal". According to another explanation, the words "Newar" and "Newari" are colloquial forms arising from the mutation of P to W, and L to R. There are regarded as the Adivasi of Kathmandu Valley.

As a result of the phonological process of dropping the last consonant and lengthening the vowel, "Newā" for Newār or Newāl, and "Nepā" for Nepāl are used in ordinary speech.

For over two millennia, the Newa civilization in Central Nepal preserved a microcosm of classical North Indian culture in which Brahmanic and Buddhist elements enjoyed equal status. Snellgrove and Richardson (1968) speak of 'the direct heritage of pre-Islamic India'. The Malla dynasty was noted for their patronisation of the Maithili language (the language of the Mithila region) which was afforded equal status to that of Sanskrit in the Malla court. Maithil Brahmin priests were invited to Kathmandu and many Maithil families settled in Kathmandu during Malla rule. The influx of people from both the north (Tibet) and south (Tirhut) increased not only Nepal's genetic and racial diversity but also greatly moulded the dominant culture and tradition of the Newars.

The divisions of the Newars had different historical developments. The common identity of the Newar was formed in the Kathmandu Valley. Until the conquest of the valley by the Gorkha Kingdom in 1769, all the people who had inhabited the valley at any point in time were either Newar or progenitors of Newar. So, the history of Newar correlates to the history of the Kathmandu Valley (or Nepala Mandala) prior to the establishment of the modern state of Nepal.

The earliest known history of Newar and the Kathmandu Valley blends with mythology recorded in historical chronicles. One such text, which recounts the creation of the valley, is the Swayambhu Purana. According to this Buddhist scripture, the Kathmandu Valley was a giant lake until the Bodhisattva Manjusri, with the aid of a holy sword, cut a gap in the surrounding hills and let the water out. This legend is supported by geological evidence of an ancient lakebed, and it provides an explanation for the high fertility of the Kathmandu Valley soil.