Mer, Maher or Mehar (Gujarati: ISO 15919: Mēr, Mahēr, Mēhar) is a caste from the Saurashtra region of Gujarat in India. They are largely based in the Porbandar district, comprising the Ghēḍ and Barḍā areas, and they speak a dialect of the Gujarati language. The Mers of the Ghēḍ and Barḍā form two groups of the jāti and together they are the main cultivators in Porbandar.

Mers of other lineages consider the Kēshwaḷā as the earliest lineage citing the proverb: Ādya Mēr Kēshwaḷā, jēni suraj purē chē śakh - "the sun stands testimony to the fact that Kēshwaḷās are the original Mers." An origin myth of the Kēshwaḷās descending from the neck hair of Rama was recorded by colonial authors. However, possibly the oldest reference to Kēshwaḷās indicates that the founder of this lineage may have lived over a thousand years ago, although, this relies on the genealogies of Barots which are not considered completely accurate as they are projected back in time to pseudo-history.

Mers were once associated with the Maitraka dynasty. Sinha suggests that the word Maitraka is an adaption from Mihir, which is in turn an adaption from Mer and does not rule out the possibility that the ruling families of the Maitrakas originated from the Mers. Inscriptions at the Vadava well of Cambay mentions Mers as having originated from the Solar dynasty. Other historians believe that Mers have Hun origin.

A Mer dynasty existed in Eastern Saurashtra, as noted by an inscription discovered in Timana. In 1207 CE the ruler Jagamal was a vassal of Bhima II of the Chaulukyas. Jagamal had founded the temples of Chandreshwar and Prathvidiveshwar (the last is still standing), and endowed them with 55 prājás of land from the village of Kāmlol and 55 prājás of land from the village of Phūlsar, Near the village of Kūnteli (the modern Kāndheli).

A further inscription from Mahuva, Dated to 1215 CE mentions a Mer king named Ranasimha, proposed to be a successor of king Jagamal, in the same area. The Hatasni inscription from 1328 describes the construction of a stepwell by Kuntaraja for the Mer ruler Thepak, who wanted to build a stepwell in his own name as his maternal uncle Khengar had done. Nagarjuna was born into the Vakhala family and his son Mahananda had Thepak by his wife Rupa, the daughter of Mandalik I. Thepak had been appointed to rule over Talaja by a Chudasama ruler named Mahisa. The Sīsodiyā branch of Mers was formed when the Sisodia Hati Rajputs came from Mewar in Rajasthan to Saurashtra as mercenary warriors and settled at Malia Hatina (Malia of the Hatis) and intermarried with the local Ahirs and Mers.

An inscription from Bhavnagar mentions the Mer as king of Dvija.

The Arab historian Al-Baladhuri mentioned the Mers as being a powerful tribe residing in north-west Saurashtra.

Historically, the men served the Porbandar State as a feudal militia, led by Mer leaders.