After 1870, during the reign of King Chulalongkorn Rama V, Siam began introducing European reforms, including a public school system. A school for the royal children was created in 1871, although a public system for ordinary children was not put in until after 1880. (The creation of the royal school formed the theme for the play and movie The King and I, which gives such a ridiculous and inaccurate view of Siam at the time that the movie was banned in Thailand). The reforms, however, did not prevent further concessions to the colonial powers, and territories were ceded to Britain on the Malay peninsula, and to France along the borders of Laos and Cambodia.

Siam also offered economic concessions, but even if these treaties were unequal (they favoured the European powers over Siam), they did give Siam de facto recognition as a sovereign state. The Thais also managed the fine balancing act of surviving as a buffer state between the British and French Asian empires. All of this may have offered slim protection against European domination, but unlike so many other Asian and African nations that had come into contact with the Europeans, the kingdom retained its independence.

In 1893, King Chulalongkorn recognized the French protectorate over Laos. In 1896, France and Britain offered guarantees of Siam's neutrality. In 1907, the borders between French Indo-China and Siam were fixed. The nation remained neutral for most of the First World War, but joined the Western Allies in 1917.

The Dutch, from their base on Java, consolidate their colonies in the East Indies. This leads to a long war in western Sumatra against the still independent Islamic state of Atjeh. The Atjeh wars for the Dutch were something like the Vietnam War in the 1960s and 70s for the United States. After a long struggle marked by guerrilla fighting in the mountains and jungle, Atjeh was finally occupied in 1908, but effective control was never really established.

At this time the foreign powers also took over the east Asian states, Burma and Vietnam, that had previously acknowledged Chinese suzerainty and had given tribute to the Manchu emperor (in other words, while the Manchu were not strong enough to control these countries, they would launch military raids unless they were paid money and other goods as tribute). France colonized Cochin China, as southern Vietnam was then called, and by 1864 established a protectorate over Cambodia. Following a victorious war against China in 1884-85, France also took Annam, which gave it control over all of Vietnam. Britain gained control over Burma.