In 1964, Singapore witnessed racial riots that erupted during the Mawlid procession, celebrating the birthday of the Islamic prophet Muhammad. The procession, attended by 25,000 Malay-Muslims, saw confrontations between Malays and Chinese, which spiraled into widespread unrest. While initially perceived as spontaneous, the official narrative suggests that UMNO and the Malay-language newspaper, Utusan Melayu, played a role in inciting tensions. This was exacerbated by the newspaper's portrayal of the eviction of Malays for urban redevelopment, omitting that Chinese residents were also evicted. Meetings led by Lee Kuan Yew with Malay organizations, aiming to address their concerns, further fueled tensions. Leaflets spread rumors of Chinese attempting to harm Malays, further inflaming the situation and culminating in the riots on 21 July 1964.

The aftermath of the July riots revealed conflicting viewpoints on its origins. While the Malaysian government blamed Lee Kuan Yew and PAP for fomenting Malay discontent, the PAP leadership believed that UMNO was purposefully stoking anti-PAP sentiments among Malays. The riots significantly strained relations between UMNO and PAP, with Tunku Abdul Rahman, Malaysia's Prime Minister, repeatedly criticizing the PAP's non-communal politics and accusing them of interfering in UMNO's affairs. These ideological clashes and the racial riots played a pivotal role in the eventual separation of Singapore from Malaysia, leading to Singapore's declaration of independence on 9 August 1965.

The 1964 race riots have had a profound impact on Singapore's national consciousness and policies. While the official narrative often emphasizes the political rift between UMNO and PAP, many Singaporeans recall the riots as stemming from religious and racial tensions. Following the riots, Singapore, after gaining independence, emphasized multiculturalism and multiracialism, enshrining non-discriminatory policies in the Singapore Constitution. The government also introduced educational programs and commemorations, like Racial Harmony Day, to educate younger generations on the importance of racial and religious harmony, drawing lessons from the tumultuous events of 1964.