Johor is a state of Malaysia in the south of the Malay Peninsula. It borders with Pahang, Malacca and Negeri Sembilan to the north. Johor has maritime borders with Singapore to the south and Indonesia to the east and west. As of 2023, the state's population is 4.09 million, making it the second most populous state in Malaysia, after Selangor. Johor Bahru is the capital city and the economic centre of the state, Kota Iskandar is the state administrative centre and Muar serves as the royal capital.

As one of the nation's most important economic hubs, Johor has the highest gross domestic product (GDP) in Malaysia outside of the Klang Valley, making it the country's second largest state economy, behind Selangor. Its household income and total salaries are the second highest among all Malaysian states. Johor has the world's second largest artificial intelligence hub, robust manufacturing and logistics centres, and home to the Port of Tanjung Pelepas, the 15th busiest port in the world. Iskandar Malaysia, which covers much of southern Johor, is the country's largest special economic zone by investment value.

Johor has high diversity in ethnicity, culture, language, and is known for its traditional dance of zapin and kuda kepang. The head of state is the Sultan of Johor, while the head of government is the Chief Minister. The government system is closely modelled on the Westminster system. Johor is divided into administrative districts, with Johor Bahru District being the second largest district in Malaysia by population and economy. Islam is the state religion, but other religions can be freely practised. Johor has diverse tropical rainforests and an equatorial climate. Situated at the southern foothills of the Tenasserim Hills, inselbergs and massifs dominate the state's flat landscape, with Mount Ledang being the highest point.

The area was first known to the northern inhabitants of Siam as Gangganu or Ganggayu (Treasury of Gems) due to the abundance of gemstones near the Johor River. Arab traders referred to it as جَوْهَر‎ (‏jauhar‎), a word borrowed from the Persian گوهر‎ (gauhar), which also means 'precious stone' or 'jewel'. As the local people found it difficult to pronounce the Arabic word in the local dialect, the name subsequently became Johor. Meanwhile, the Old Javanese eulogy of Nagarakretagama called the area Ujong Medini ('land's end'), as it is the southernmost point of mainland Asia. Another name, through Portuguese writer Manuel Godinho de Erédia, made reference to Marco Polo's sailing to Ujong Tanah (the end of the Malay Peninsula land) in 1292. Both Ujong Medini and Ujong Tanah had been mentioned since before the foundation of the Sultanate of Malacca. Throughout the period, several other names also co-existed such as Galoh, Lenggiu and Wurawari. Johor is also known by its Arabic honorific as دارالتّعظيم‎ (Darul Ta'zim) or 'Abode of Dignity'.

A bronze bell estimated to be from 150 AD was found in Kampong Sungai Penchu near the Muar River. The bell is believed to have been used as a ceremonial object rather than a trade object as a similar ceremonial bell with the same decorations was found in Battambang province, Cambodia, suggesting that the Malay coast came in contact with Funan, with the bell being a gift from the early kingdom in mainland Asia to local chieftains in the Malay Peninsula. Another important archaeological find was the ancient lost city of Kota Gelanggi, which was discovered by following trails described in an old Malay manuscript once owned by Stamford Raffles. Artefacts gathered in the area have reinforced claims of early human settlement in the state. The claim of Kota Gelanggi as the first settlement is disputed by the state government of Johor, with other evidence from archaeological studies conducted by the state heritage foundation since 1996 suggesting that the historic city is actually located in Kota Tinggi District at either Kota Klang Kiu or Ganggayu. The exact location of the ancient city is still undisclosed, but is said to be within the 14,000-hectare (34,595-acre) forest reserve where the Lenggiu and Madek Rivers are located, based on records in the Malay Annals that, after conquering Gangga Negara, Raja Suran from Siam of the Nakhon Si Thammarat Kingdom (Ligor Kingdom) had sailed to Ganggayu. Since ancient times, most of the coastal Malay Peninsula has had their own rulers, but all fell under the jurisdiction of Siam.

After the fall of Malacca in 1511 to the Portuguese, the Johor Sultanate was established by Sultan Mahmud Shah of Malacca's son, Ala'udin Ri'ayat Shah II, in 1528 when he moved the royal court to the Johor River and set up his royal residence in Johor Lama. Johor became an empire spanning the southern Malay Peninsula, Riau Archipelago (including Singapore), Anambas Islands, Tambelan Archipelago, Natuna Islands, a region around the Sambas River in south-western Borneo and Siak in Sumatra with Pahang, Aru and Champa as allies. It aspired to retake Malacca from the Portuguese which the Aceh Sultanate in northern Sumatra also aspired to do leading to a three-way war among the rivals. During the wars, Johor's administrative capital moved several times based on military strategies and to maintain authority over trading in the region. Johor and the Portuguese began to collaborate against Aceh, which they saw as a common enemy. In 1582 the Portuguese helped Johor thwart an attack by Aceh, but the arrangement ended when Johor attacked the Portuguese in 1587. Aceh continued its attacks against the Portuguese, and only ceased when a large armada from the Portuguese port in Goa came to defend Malacca and destroy the sultanate.

After Aceh was left weakened, the Dutch East India Company (VOC) arrived and Johor formed an alliance with them to eliminate the Portuguese in the 1641 capture of Malacca. Johor regained authority over many of its former dependencies in Sumatra, such as Siak (1662) and Indragiri (1669), which had fallen to Aceh while Malacca was taken by the Dutch. Malacca was placed under the direct control of Batavia in Java. Although Malacca fell under Dutch authority, the Dutch did not establish any further trading posts in the Malay Peninsula and Sumatra, as they had more interest in Java and the Maluku Islands. The Dutch only become involved with local disputes when the Bugis began to threaten their maritime trade.

The dynasty that descended from the rulers of Malacca lasted until the death of Mahmud II, when it was succeeded by the Bendahara dynasty, a dynasty of ministers who had previously served in the Malacca Sultanate. The Dutch felt increasingly threatened in the 18th century, especially when the English East India Company started to establish a presence in the northern Malay Peninsula, leading the Dutch to seize the Bugis areas of Riau and expel the Bugis from both Riau and Selangor so these areas would not fall under British rule. This ended Bugis political domination in the Johor-Pahang-Riau empire, resulting in the Bugis being banned from Riau in 1784. During the rivalry between the Bugis and Dutch, Mahmud Shah III concluded a treaty of protection with the VOC on board the HNLMS Utrecht and the sultan was allowed to reside in Riau with Dutch protection. Since then, mistrust between the Bugis and Malay escalated. From 1796 to 1801 and from 1807 to 1818, Malacca was placed under British Residency as the Netherlands were conquered by France in the Napoleonic Wars and was returned to the Dutch in 1818. Malacca served as the staging area for the British Invasion of Java in 1811.