Koreans in Vietnam is a community of Vietnam with a population of Korean expatriates along with Vietnamese citizens of Korean ancestry. The population initially came in a military capacity, fighting on both sides of the Vietnam War. After the end of the war, there was little Korean migration or tourism in Vietnam, until the rise of the South Korean economy and the decline of the North resulted in an influx of South Korean investors and North Korean defectors, as well as South Korean men seeking Vietnamese wives. As of 2011, according to statistics of South Korea's Ministry of Foreign Affairs and Trade, they numbered roughly eighty thousand people, making them the second-largest Korean diaspora community in Southeast Asia, after the Korean community in the Philippines, and the tenth-largest in the world. A more recent estimate from Vietnam Television says their population might be as large as 130,000.
Both North and South Korea lent material and manpower support to their respective ideological allies during the Vietnam War, though the number of South Korean troops on the ground was larger. Then-South Korean president Syngman Rhee had offered to send troops to Vietnam as early as 1954, but his proposal was turned down by the U.S. Department of State; the first South Korean personnel to land in Vietnam, 10 years later, were non-combatants: ten Taekwondo instructors, along with thirty-four officers and ninety-six enlisted men of a Korean Army hospital unit. In total, between 1965 and 1973, 312,853 South Korean soldiers fought in Vietnam; According to Korean sources, they killed 41,400 North Vietnamese Army soldiers and 5,000 civilians. There were cases of war atrocities in which those that were revealed during the war were promptly investigated with the perpetrators punished. However, controversy still remains as there are more alleged crimes that may not have been revealed. There were also thousands of children of mixed Korean and Vietnamese descent.
As a result of a decision of the Korean Workers' Party in October 1966, in early 1967 North Korea sent a fighter squadron to North Vietnam to back up the North Vietnamese 921st and 923rd fighter squadrons defending Hanoi. They stayed through 1968; 200 pilots were reported to have served. In addition, at least two anti-aircraft artillery regiments were sent as well.
Four years after the 1992 normalisation of diplomatic ties, South Korean trade and investment in Vietnam grew rapidly. Following along with the investment funds, the South Korean expatriate community in Vietnam has grown significantly. According to Chang Keun Lee of the Korean Chamber of Commerce and Industry in Vietnam, Koreans formed the country's second-largest group of expatriates, with only the Taiwanese expatriate community being larger; he estimated that half lived in Ho Chi Minh City. Statistics from South Korea's Ministry of Foreign Affairs and Trade show that their population has grown by nearly fifty times in little more than a decade. Their population more than trebled from 1,788 in 1997 to 6,226 in 2003, then jumped to more than thirteen times that size—84,566—by just six years later. However, in the two years after that, the population would only grow by a further 4% to 88,120. Some anti-Korean sentiment also exists, fueled by decreases in promised investment, reports of poor treatment faced by Vietnamese migrants in South Korea, and the 2008 murder of a Hanoi National University student by her South Korean boyfriend. As both two countries also share common heritages and over 1/4 Koreans have Vietnamese descent, South Korean investors soon take a strong influence in Vietnam.
Before 2004, thousands of North Korean defectors had crossed Vietnam's northern border to find the way to reach South Korea. Until 2004, Vietnam was described as the "preferred Southeast Asian escape route" for North Korean defectors, largely due to its less-mountainous terrain. Though Vietnam remains an officially communist country and maintains diplomatic relations with North Korea, growing South Korean investment in Vietnam has prompted Hanoi to quietly permit the transit of North Korean refugees to Seoul. The increased South Korean presence in the country also proved a magnet for defectors; four of the biggest defector safehouses in Vietnam were run by South Korean expatriates, and many defectors indicated that they chose to try to cross the border from China into Vietnam precisely because they had heard about such safehouses. In July 2004, 468 North Korean refugees were airlifted to South Korea in the single largest mass defection; Vietnam initially tried to keep their role in the airlift secret, and in advance of the deal, even anonymous sources in the South Korean government would only tell reporters that the defectors came from "an unidentified Asian country". Following the airlift, Vietnam would tighten up border controls and deport several safe-house operators.
Vietnam's first school for South Korean nationals, the weekend Hanoi Hangul School, was founded on 1 March 1996, enrolling 122 students at the kindergarten through middle school levels; two Korean international schools offering a full-day programme were also later established, the Korean International School, HCMC in Ho Chi Minh City (founded 4 August 1998, enrolling 745 students at the kindergarten through high school levels); and Hanoi Korean International School, a smaller school in Hanoi (founded 13 July 2006, with 63 elementary-level students). Prior to the opening of the Korean international school in Hanoi, most Korean families in Hanoi sent their children to local schools, as the other international schools were too expensive.
South Korean men started seeking wives in Vietnam. Two to three thousand South Korean marriage agencies were created which specialise in making such matches. Though in the 1990s, most were farmers, an increasing number of urban men have also resorted to arranging marriages through international matchmaking agencies; they cite the difficulty faced by uneducated men or those with low incomes in attracting South Korean women to marry them. As of 2006, as many as 3,000 Vietnamese brides left with new South Korean husbands every year.