The Manila galleon (Spanish: Galeón de Manila; Tagalog: Galeon ng Maynila) refers to the Spanish trading ships that linked the Philippines in the Spanish East Indies to Mexico (New Spain), across the Pacific Ocean. The ships made one or two round-trip voyages per year between the ports of Manila and Acapulco from the late 16th to early 19th century. The term "Manila galleon" can also refer to the trade route itself between Manila and Acapulco that was operational from 1565 to 1815.

The Manila galleon trade route was inaugurated in 1565 after the Augustinian friar and navigator Andrés de Urdaneta pioneered the tornaviaje or return route from the Philippines to Mexico. Urdaneta and Alonso de Arellano made the first successful round trips that year, by taking advantage of the Kuroshio Current. The galleons set sail from Cavite, in Manila Bay, at the end of June or the first week of July, sailing through the northern Pacific and reaching Acapulco in March to April of the next calendar year. The return route from Acapulco passes through lower latitudes closer to the equator, stopping over in the Marianas, then sailing onwards through the San Bernardino Strait off Cape Espiritu Santo in Samar and then to Manila Bay and anchoring again off Cavite by June or July. The trade using "Urdaneta's route" lasted until 1815, when the Mexican War of Independence broke out. The majority of these galleons were built and loaded in shipyards in Cavite, utilizing native hardwoods like the Philippine teak, with sails produced in Ilocos, and with the rigging and cordage made from salt-resistant Manila hemp. The vast majority of the galleon's crew consisted of Filipino natives; many of whom were farmers, street children, or vagrants press-ganged into service as sailors. The officers and other skilled crew were usually Spaniards (a high percentage of whom were of Basque descent). The galleons were state vessels and thus the cost of their construction and upkeep was borne by the Spanish Crown.

The galleons mostly carried cargoes of Chinese and other Asian luxury goods in exchange for New World silver. Silver prices in Asia were substantially higher than in America, leading to an arbitrage opportunity for the Manila galleon. Every space of the galleons was packed tightly with cargo, even spaces outside the holds like the decks, cabins, and magazines. In extreme cases, they towed barges filled with more goods. While this resulted in slow passage (which sometimes resulted in shipwrecks or turning back), the profit margins were so high that it was commonly practiced. These goods included Indian ivory and precious stones, Chinese silk and porcelain, cloves from the Moluccas islands, cinnamon, ginger, lacquers, tapestries and perfumes from all over Asia. In addition, slaves (collectively known as "chinos") from various parts of Asia (mainly slaves bought from the Portuguese slave markets and Muslim captives from the Spanish–Moro conflict) were also transported from the Manila slave markets to Mexico. Free indigenous Filipinos also migrated to Mexico via the galleons (including galleon crew that jumped ship), comprising the majority of free Asian settlers ("chinos libres") in Mexico, particularly in regions near the terminal ports of the Manila galleons. The route also fostered cultural exchanges that shaped the identities and the culture of the countries involved.

The Manila galleons were also known colloquially in New Spain as La Nao de China ("The China Ship") because they carried mostly Chinese goods shipped from Manila. The Manila Galleon route was an early instance of globalization, representing a trade route from Asia that crossed to the Americas, thereby connecting all the world's continents in global silver trade.

In 2015, the Philippines and Mexico began preparations for the nomination of the Manila–Acapulco Galleon Trade Route in the UNESCO World Heritage List with backing from Spain, which has also suggested the tri-national nomination of the archives on the Manila–Acapulco Galleons in the UNESCO Memory of the World Register.

In 1521, a Spanish expedition led by Ferdinand Magellan sailed west across the Pacific using the westward trade winds. The expedition discovered the Mariana Islands and the Philippines and claimed them for Spain. Although Magellan was killed by natives commanded by Lapulapu during the battle of Mactan in the Philippines, one of his ships, the Victoria, made it back to Spain by continuing westward.

To settle and trade with these islands from the Americas, an eastward maritime return path was necessary. The Trinidad, which tried this a few years later, failed. In 1529, Álvaro de Saavedra Cerón also tried sailing east from the Philippines, but could not find "westerlies" across the Pacific. In 1543, Bernardo de la Torre also failed. In 1542, however, Juan Rodríguez Cabrillo helped pave the way by sailing north from Mexico to explore the Pacific coast, reaching just north of the 38th parallel at the Russian River. The frustration of these failures is shown in a letter sent in 1552 from Portuguese Goa by the Spanish missionary Francis Xavier to Simão Rodrigues asking that no more fleets attempt the New Spain–East Asia route, lest they be lost.

Despite prior failures navigator Andrés de Urdaneta effectively persuaded Spanish officials in New Spain that a Philippines-Mexico trade route was preferable to other alternatives. He argued against direct trade between Spain and the Philippines through the strait of Magellan on the basis that climate would make passage through the strait possible only during summer and that therefore ships would need to stay the winter in a more northern port. His preference for Mexico rather than for the shorter overland route through Darién is thought to have been due to his links to Pedro de Alvarado.