Malappuram district (Malayalam: [mɐlɐpːurɐm] ^ⓘ), is one of the 14 districts in the Indian state of Kerala, with a coastline of 70 km (43 mi). The most populous district of Kerala, Malappuram is home to around 13% of the total population of the state. The district was formed on 16 June 1969, spanning an area of about 3,554 km² (1,372 sq mi). It is the third-largest district of Kerala by area. It is bounded by Western Ghats and the Arabian Sea on either side. The district is divided into seven Taluks: Eranad, Kondotty, Nilambur, Perinthalmanna, Ponnani, Tirur, and Tirurangadi.

Malayalam is the most spoken language. The district has witnessed significant emigration, especially to the Arab states of the Persian Gulf during the Gulf Boom of the 1970s and early 1980s, and its economy depends significantly on remittances from a large Malayali expatriate community. Malappuram was the first e-literate as well as the first cyber literate district of India. The district has four major rivers, namely Bharathappuzha, Chaliyar, Kadalundippuzha, and Tirur Puzha, out of which the first three are also among the five longest rivers in Kerala.

Malappuram metropolitan area is the fourth largest urban agglomeration in Kerala after Kochi, Calicut, and Thrissur urban areas and the 25th largest in India with a total population of 1.7 million. 44.2% of the district's population reside in the urban areas according to the 2011 census of India. Being home to 4 universities in the state, including the University of Calicut, Malappuram is a hub of higher education in Kerala. The district comprises 2 revenue divisions, 7 taluks, 12 municipalities, 15 blocks, 94 Grama Panchayats, and 16 Kerala Legislative Assembly constituencies in it.

During British Raj, Malappuram became the headquarters of foreign and Indian troops and later of the Malabar Special Police (M.S.P), formerly known as Malappuram Special Force formed in 1885, which is also the oldest armed police battalion in the state. The oldest Teak plantation in the world at Conolly's plot is situated at Chaliyar valley in Nilambur. The oldest Railway line in the state was laid from Tirur to Chaliyam in 1861, passing through Tanur, Parappanangadi, and Vallikkunnu. The second railway line in the state was also laid in the same year from Tirur to Kuttippuram via Tirunavaya. The Nilambur–Shoranur line, also laid in the colonial era, is one among the shortest and picturesque Short Gauge Railway Lines in India.

The term, Malappuram, which means "over the hill" in Malayalam, derives from geography of Malappuram, the administrative headquarters of the district. The midland area of district is characterised by several undulating hills such as Arimbra hills, Amminikkadan hills, Oorakam Hill, Cheriyam hills, Pandalur hills, and Chekkunnu hills, all of which lie away from the Western Ghats. However, the coconut-fringed sandy coastal plain is an exception for the general hilly nature.

The remains of pre-historic symbols including Dolmens, Menhirs, and Rock-cut caves have found from various parts of district. Rock-cut caves have found from Puliyakkode, Thrikkulam, Oorakam, Melmuri, Ponmala, Vallikunnu, and Vengara. The ancient maritime port of Tyndis, which was then a centre of trade with Ancient Rome, is roughly identified with Ponnani, Tanur, and Kadalundi-Vallikkunnu-Chaliyam-Beypore region. Tyndis was a major center of trade, next only to Muziris, between the Cheras and the Roman Empire. Pliny the Elder (1st century CE) states that the port of Tyndis was located at the northwestern border of Keprobotos (Chera dynasty). The region, which lies north of the port at Tyndis, was ruled by the kingdom of Ezhimala during Sangam period. According to the Periplus of the Erythraean Sea, a region known as Limyrike began at Naura and Tyndis. However the Ptolemy mentions only Tyndis as the Limyrike's starting point. The region probably ended at Kanyakumari; it thus roughly corresponds to the present-day Malabar Coast. The value of Rome's annual trade with the region was estimated at around 50,000,000 sesterces. Pliny the Elder mentioned that Limyrike was prone by pirates. The Cosmas Indicopleustes mentioned that the Limyrike was a source of peppers. The river Bharathappuzha (River Ponnani) had importance since Sangam period (1st–4th century CE), due to the presence of Palakkad Gap which connected the Malabar coast with Coromandel coast through inland.

The Kurumathur inscription found near Areekode dates back to 871 CE. Three inscriptions written in Old Malayalam those date back to 932 CE, those were found from Triprangode (near Tirunavaya), Kottakkal, and Chaliyar, mention the name of Goda Ravi of Chera dynasty. The Triprangode inscription states about the agreement of Thavanur. Several inscriptions written in Old Malayalam those date back to the 10th century CE, have found from Sukapuram near Edappal, which was one of the 64 old Nambudiri villages of Kerala.

Descriptions about the rulers of Eranad and Valluvanad regions can be seen in the Jewish copper plates of Bhaskara Ravi Varman (around 1000 CE) and Viraraghava copper plates of Veera Raghava Chakravarthy (around 1225 CE). The Zamorin of Calicut originally belonged to Nediyiruppu at Kondotty in Eranad before he shifted his seat to the neighbouring Kozhikode. Eranad was ruled by a Samanthan clan known as Eradis, similar to the Vellodis of neighbouring Valluvanad and Nedungadis of Nedunganad. The rulers of Eranad were known by the title Eralppad/Eradi. It was the ruler of Eranad (Eradi of Nediyiruppu) who established the kingdom of Calicut and developed Kozhikode as a major port city in the Malabar Coast. Just after that, the rulers of Parappanad (Parappanangadi) and the Vettathunadu (Tanur) became vassals of Zamorin. The Parappanad royal family is a cousin dynasty of Travancore royal family. Besides, a larger portion of Valluvanad Kovilakams (Nilambur, Manjeri, Malappuram, Kottakkal, and Ponnani) also became vassals of the Zamorin.