Har or HAR may refer to:

• Har (Blake), a character in the mythological writings of William Blake
• Hár (crater), a crater on Jupiter's moon Callisto
• Har, another name for the Hindu god Shiva
• Har, another name for the Egyptian god Horus
• Hursag, the Sumero-Akkadian ideogram for "mountain"
• Hár (meaning "high"), one of the many names of Odin in Norse mythology
• Har, a term associated with Wraeththu, humanoid species in the six-part Storm Constantine fantasy series
• Han Ah Reum, or H Mart
• Heritage at Risk, English Heritage's register of endangered historic heritage
• Human accelerated regions, the name of some human genes
• .har (HTTP Archive), a file format that can be used by HTTP monitoring tools to export collected data
• Hacking at Random, an outdoor hacker conference that took place in Netherlands in the summer of 2009
• Highway advisory radio, another name for travelers' information station, a form of broadcast traffic information

The HTTP Archive format or HAR, is a JSON-formatted archive file format for logging of a web browser's interaction with a site. The common extension for these files is .har.

Hár is a crater on Jupiter's moon Callisto. Its name is one of the many names of Odin, the supreme god in Norse mythology. This is an example of a central dome impact crater.

Paul Auguste Hariot (1854 - 5 July 1917), the son of Louis Hariot (also a pharmacist), was a French pharmacist and noted phycologist, best known for his 1900 publication Atlas Colorié des Plantes Médicinales Indigènes]  Hariot took up the position of botanical assistant at the École Supérieure de Pharmacie in the late 1870s during his training in pharmacy in Paris. On qualifying in 1882, his rather quiet and studious life was changed by an invitation to accompany the botanist Émile Bescherelle (1828-1903) on an expedition to Cape Horn aboard the ship La Romanche, a trip during which he amassed a fine collection of algae. On returning to France he studied natural sciences and was awarded a degree in 1888 whereupon he joined the National Museum of Natural History in Paris, working in the cryptogamic herbarium under Professor van Tieghem. Here he worked on classifying specimens that had been gathered by Sébastien Vaillant (1669-1722), and those of the brothers Edmond and Charles Tulasne. He revised when necessary the taxonomy and systematics of the species described, and his name appears frequently as a second author for many species of algae. In 1890 he was awarded the Prix Montagne by the Academy of Sciences for his monograph on terrestrial algae of the genus Trentepohlia. He was awarded the Prix Desmazières for 1913 for his work on marine flora.