Cambodia’s Major Dilemma: Handling Anti-Vietnamese Sentiments

INTRODUCTION

The historical relationship between Cambodia and Vietnam has seen periods of cooperation and conflict. Widespread anti-Vietnamese sentiments in Cambodia date back to the 17^th century, rooted in perceived injustices and territorial disputes, and later intensified by French colonisation. These sentiments have led to Cambodian national identity being often defined in opposition to Vietnamese influence. For the Cambodian government, managing these sentiments is vital in ensuring social stability, maintaining national sovereignty, and enhancing Cambodia’s international reputation.

This article investigates the root causes of anti-Vietnamese sentiments in Cambodia, focusing on historical tensions, colonial legacies, and contemporary political dynamics. It also examines the present Cambodian government’s response, including direct actions like immigration reforms and diplomacy, as well as indirect efforts such as curbing anti-Vietnam rhetoric. The study highlights Cambodia’s persistent challenges in fostering national unity and promoting peaceful coexistence with Vietnam.

HISTORICAL CAUSES OF ANTI-VIETNAMESE SENTIMENTS

Anti-Vietnamese sentiments in Cambodia trace back at least to 1620, when King Chey Chettha II married Vietnamese princess Nguyen Phuc Ngoc Van. A myth from the Chenla Kingdom era claims the Khmer King ceded Kampuchea Krom (the south-western part of modern-day Vietnam) to Vietnam for this marriage and to gain Vietnamese support against Ayutthaya to the west. This marriage marked the first political alliance between the two nations and the beginning of Vietnam’s influence in Cambodia. It also paved the way for Vietnamese settlement in the Mekong Delta. The 18^th to 19^th centuries saw more intense Vietnamese settlement in this area, and by the time France established colonial control over southern Vietnam in the 19^th century, the Vietnamese effectively dominated the region, including through administrative structures that allowed them to claim ownership of the land.

French colonisation further intensified anti-Vietnamese sentiments by consolidating Cambodia, Vietnam, and Laos into the Indochinese Federation that was officially formed in 1887. Ignoring historical boundaries and local aspirations, France made territorial adjustments which sparked disputes among the three nations. A key example is the French government’s formal recognition of Kampuchea Krom as part of Vietnam through Law 49-733 signed by French President Vincent Auriol on 4 June 1949.

After Vietnam and Cambodia gained their independence from France, anti-Vietnamese sentiments in Cambodia continued to grow following an influx of Vietnamese migrants seeking economic opportunities. This was perceived by many Cambodians as a threat to national sovereignty and territorial integrity. The 1962 Cambodian census reported 218,000 Vietnamese (3.8% of the country’s population of 5.7 million) living in the country. Before the 1970 Lon Nol coup, the Vietnamese population was estimated at 400,000–450,000 out of 6.7 million, making them Cambodia’s largest minority. In response, the Lon Nol regime (1970–1975) launched anti-Vietnamese campaigns, expelling 200,000–250,000 ethnic Vietnamese to Vietnam and killing thousands. After Pol Pot’s rise in April 1975, a further 150,000 ethnic Vietnamese were expelled. In 1977, the Khmer Rouge ordered mass executions which left thousands dead; reports suggested that only a few thousand ethnic Vietnamese had survived by year’s end. In 1979, the Vietnamese army overthrew the Khmer Rouge, and established the pro-Vietnam People’s Republic of Kampuchea. Many Cambodians came to view the decade-long Vietnamese occupation (1979–89) as control rather than liberation.

These historical grievances continue to shape many Cambodians’ perceptions. For instance, in August 2022, a small group of young people protested against the establishment of the Department of Vietnamese Studies at the Royal University of Phnom Penh. These protesters argued that the department might spread negative Vietnamese cultural and political influence in Cambodia. Similarly, in August 2024, thousands of Cambodians in South Korea, Japan, and Australia protested against Cambodia’s participation in the Cambodia–Laos–Vietnam Development Triangle Area (CLV-DTA), expressing fear of potential territorial encroachment by Vietnam if the agreement remained in force.

MANAGING ANTI-VIETNAMESE SENTIMENTS

Against this backdrop, it is crucial for the Cambodian government to actively manage anti-Vietnamese sentiments. First, legitimacy is a significant concern for the ruling Cambodian People’s Party (CPP). Accusations that the CPP government favours Vietnamese interests over those of its own citizens, although unsupported by credible evidence, can damage the CPP’s reputation among segments of the population. Second, managing these sentiments effectively can foster social and political stability. Heightened tensions can lead to community divisions, and distract from the importance of essential issues like poverty alleviation, education, and infrastructure. Third, limiting anti-Vietnamese sentiments can enhance Cambodia’s international image and potentially increase foreign investment, tourism, and collaboration. Countries prefer to engage with nations that demonstrate social harmony and a commitment to human rights. Fourth, effectively managing anti-Vietnamese sentiment in the country enables the government to maintain cordial relations with Vietnam, a relationship that is crucial to Cambodia’s security and development. It should be noted that the Vietnamese government has repeatedly called on Cambodia to protect Vietnamese-origin communities within its borders, who they claim face regular discrimination and harassment.

As prime minister, Hun Manet—who does not share his father’s close relationship with the Vietnamese leadership—enjoys greater flexibility in addressing nationalist sentiments.

The Cambodian government addresses these anti-Vietnamese sentiments both directly and indirectly. Direct measures include managing illegal Vietnamese immigration and withdrawing from the CLV-DTA initiative. Indirectly, they work to silence instigators of these sentiments, such as the Cambodia National Rescue Party (CNRP).

Addressing Illegal Vietnamese Immigration

To address rising anti-Vietnamese sentiments in Cambodia, the government has taken steps to manage the issue of illegal Vietnamese immigrants. According to data available in 2017, there were an estimated 400,000 to 700,000 legal and illegal ethnic Vietnamese in Cambodia. In response to this situation, the government has initiated significant measures, including the documentation and deportation of Vietnamese immigrants. One of the most prominent efforts began in 2017 with a campaign to revoke “irregular administrative documents” held by approximately 70,000 individuals, the majority of whom were of Vietnamese descent. Here, “revocation” refers to the official invalidation of documents deemed to have been issued improperly, such as birth certificates, old immigration cards, passports, national identification cards, and other forms of legal documentation. It is notable that many Vietnamese families have resided in areas like Tonle Sap Lake for generations. Despite their long-term residence, many still lacked official recognition.

Furthermore, since 2015, the government has deported 4,424 undocumented foreigners, of whom 3,978—or about 90 per cent—were Vietnamese nationals. In 2024 alone, the Cambodian government expelled 2,159 foreign nationals for legal violations, including 507 Vietnamese.

The government justified these actions by citing administrative irregularities and improper issuance of legal documents, claiming that many ethnic Vietnamese had obtained official papers through irregular channels or without following appropriate legal procedures. These measures were largely seen as a response to growing nationalist pressures and the lingering historical resentment toward ethnic Vietnamese. By revoking these documents, the Cambodian government aimed to regulate its immigration system and standardise legal residency status. Many Cambodians perceived this crackdown to be necessary for appeasing nationalist groups and reinforcing national sovereignty.

Withdrawing from the CLV-DTA

On 20 September 2024, Cambodia announced its withdrawal from the CLV-DTA, a 25-year-old trilateral agreement between Cambodia, Laos, and Vietnam. This agreement was originally concluded under former Prime Minister Hun Sen. The move was largely interpreted as a response to mounting anti-Vietnam sentiments and nationalist fervour within the country. Critics of the agreement had claimed that the CLV-DTA led to deforestation and border disputes, and posed a threat to Cambodian territorial integrity. They particularly accused the CPP government of ceding the northeastern provinces of Ratanakiri, Stung Treng, Kratie, and Mondulkiri to Vietnam. These accusations intensified public dissatisfaction, and threatened to destabilise the ruling party.

Initially, the Cambodian government maintained a strong defence of the CLV-DTA, highlighting its significance in promoting regional cooperation and the economic development of the northeastern provinces. The government also reassured the public that no territorial swaps would occur under the agreement. Cambodia and Vietnam also signed an agreement in 2005, which—together with the 1985 Border Treaty—provides the legal framework for demarcating their shared boundary. As a result, Cambodia began demarcating its border with Vietnam and installing border posts in 2007, demonstrating its commitment to protecting its territorial integrity. According to Prime Minister Hun Manet, over the past 25 years, more than 150 border posts have been erected in Kratie Province alone; of these, 11 are main posts and 144 are auxiliary posts.

Despite these reassurances, concerns over sovereignty and the rapid spread of misinformation by nationalist groups forced the government to reconsider its position. The controversy surrounding the CLV-DTA quickly gained traction in the Cambodian diaspora in South Korea, Australia, and Japan, where protests were staged to demand Cambodia’s withdrawal. The discontent culminated in domestic demonstrations on 18 August 2024, which led to the arrest of more than 66 people. While many arrestees were subsequently released, protest leaders continue to face charges.

Confronted with mounting domestic pressure and the desire to counter growing anti-Vietnam sentiments, Prime Minister Hun Sen and his successor, Hun Manet, alongside other political leaders, ultimately decided to withdraw Cambodia from the CLV-DTA. This withdrawal signalled the CPP’s attentiveness to nationalist concerns and its commitment to safeguarding territorial integrity, even at the expense of regional economic engagement. The move may also have been intended to smooth the transfer of power from Hun Sen to his son. As prime minister, Hun Manet—who does not share his father’s close relationship with the Vietnamese leadership—enjoys greater flexibility in addressing nationalist sentiments. By allowing his predecessor to absorb much of the public scrutiny, Hun Manet has skilfully focused attention away from himself, providing him with the space needed to consolidate his leadership, rebuild public trust, and bolster the credibility of the ruling party.

Silencing the Instigators

The Cambodian government also needs to ensure that there are no credible sources intensifying anti-Vietnamese sentiments within the country. Over the past three decades, the primary instigator of such sentiments has largely been the Cambodia National Rescue Party (CNRP), an opposition party. Prominent CNRP leaders have frequently used the Khmer term “Yuon” to refer to Vietnamese people, a word often considered pejorative and discriminatory. For example, in July 2013, Sam Rainsy, CNRP’s then president, stated: “All compatriots – this is the last opportunity, if we don’t rescue our nation, four or five years more is too late, Cambodia will be full of Vietnamese, we will become slaves of Vietnam.” Such rhetoric has been deployed as a political strategy aimed at discrediting the CPP, and has recurred over the past thirty years.

To prevent anti-Vietnamese sentiments from spiralling out of control, the Supreme Court of Cambodia dissolved the CNRP on 16 November 2017. The party was accused of plotting a “colour revolution” to overthrow the government, a charge its leaders vehemently denied. Kem Sokha, who succeeded Sam Rainsy as CNRP’s president in March 2017, was arrested, and all elected CNRP politicians lost their seats in the National Assembly. Sam Rainsy, however, managed to flee to France prior to the party’s dissolution.

Since CNRP membership is now treasonous under Cambodian law, advocacy for anti-Vietnamese sentiments by major political actors has become ineffective.

REMAINING CHALLENGES

Despite the Cambodian government’s strong efforts to manage anti-Vietnamese sentiment, several challenges persist. Unresolved border demarcation issues, in particular, remain significant sources of tension. The land border between Cambodia and Vietnam, stretching 1,137 kilometres through ten Vietnamese and nine Cambodian provinces, continues to be a sensitive topic. Although the 1985 Treaty on the Delimitation of National Boundaries and its 2005 Supplementary Treaty resulted in the official demarcation of approximately 84% of the land border (1,042 km), pockets of dispute remain and could reignite anti-Vietnamese sentiments at any moment, given the two countries’ complex shared history.

Moreover, maritime borders between Cambodia and Vietnam have not been formally negotiated and remain unresolved. This ambiguity encourages activities such as illegal, unreported, and unregulated (IUU) fishing, which regularly exacerbate tensions. Repeated incursions by Vietnamese fishing vessels into what is perceived as Cambodian waters have often sparked public outrage. A notable incident occurred in April 2020, when 240 Vietnamese boats allegedly entered Cambodian waters. The Vietnamese authorities have pledged to address such violations, but solutions that are both effective and timely remain crucial. Failure to act decisively could further inflame anti-Vietnamese sentiments within Cambodia and undermine broader efforts to maintain stable and friendly relations.

Unresolved border demarcation issues, in particular, remain significant sources of tension. The land border between Cambodia and Vietnam, stretching 1,137 kilometres through ten Vietnamese and nine Cambodian provinces, continues to be a sensitive topic.

Another challenge is how the Vietnamese government and public respond to the Cambodian government’s Funan Techo Canal project. If Vietnam continues to discredit the project, such criticism is likely to further fuel anti-Vietnamese sentiment within Cambodia. Based on numerous conversations the author has had with Cambodian scholars and officials, most interlocutors believe that Vietnam is actively seeking ways to delegitimize the project. Indeed, whenever Vietnamese media reports have criticised the project,Cambodian leaders and scholars have quickly defended and dismissed Vietnam’s concerns as “misplaced”. As such, if Hanoi chooses to refrain from criticising the project, anti-Vietnamese sentiment in Cambodia is likely to remain manageable. Conversely, continued criticism from Vietnam may further inflame such sentiments.

Moving forward, effectively addressing anti-Vietnamese sentiments in Cambodia demands a nuanced, multifaceted approach that goes beyond short-term political actions. It requires fostering a narrative of genuine inclusion and shared future aspirations, one that promotes mutual respect, empathy, and understanding. By promoting awareness, combating inflammatory rhetoric, and creating platforms for intercultural exchange, the Cambodian government can strengthen the country’s peaceful and mutually beneficial relationship with Vietnam and lay the groundwork for a more harmonious, resilient, and prosperous region.

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This is an adapted version of ISEAS Perspective 2025/47 published on 27 June 2025. The paper and its references can be accessed at this link.