Officially, 196 people were killed between May 13 and July 31 as a result of the riots, although journalists and other observers have stated much higher figures. The government cited the riots as the main cause of its more aggressive affirmative action policies, such as the New Economic Policy (NEP), after 1969.
The 1964 Race Riots in Singapore contributed to the expulsion of that state from Malaysia on 9 August 1965, and racial tension continued to simmer, with many Malays dissatisfied by their newly independent government's perceived willingness to placate the Chinese at their expense.
Politics in Malaysia at this time were mainly Malay-based, with an emphasis on special privileges for the Malays — other indigenous Malaysians, grouped together collectively with the Malays under the title of "bumiputra" would not be granted a similar standing until after the riots. There had been a recent outburst of Malay passion for ketuanan Melayu — a Malay term for Malay supremacy or Malay dominance — after the National Language Act of 1967, which in the opinion of some Malays, had not gone far enough in the act of enshrining Malay as the national language. Heated arguments about the nature of Malay privileges, with the mostly Chinese opposition mounting a "Malaysian Malaysia" campaign had contributed to the separation of Singapore on 9 August 1965, and inflamed passions on both sides.
The causes of the rioting can be analysed to have the same root as the 1964 riots in Singapore, the event rooted from sentiments before the 1969 general election.
Campaigning was bitterly fought among various political parties prior to polling day on 10 May 1969, and party leaders stoked racial and religious sentiments in order to win support. The Pan Malaysian Islamic Party (PAS) accused the United Malays National Organisation (UMNO) of selling the rights of the Malays to the Chinese, while the Democratic Action Party (DAP) accused Malaysian Chinese Association (MCA) of giving in to UMNO. The DAP promoted the concept of a "Malaysian Malaysia", which would deprive the Malays of their special rights under the Constitution of Malaysia. Both the DAP and Singapore's People's Progressive Party (PAP) objected to Malay as the national language and proposed multi-lingualism instead. Senior Alliance politicians, including Prime Minister Tunku Abdul Rahman, accused Singapore-based People's Action Party of involvement in the campaign, as it had done during the 1964 general election campaign (at the time when Singapore was part of the Malaysian federation between 1963 and 1965).
The run-up to the election was also marred by two deaths: that of an UMNO election agent, who was killed by a group of armed Chinese youths in Penang and that of a member of the Labour Party of Malaya (LPM), who was killed in Kepong, Selangor. There was a contrast in the handling of these two deaths. The UMNO worker was buried without publicity, but the LPM casualty was honoured at a parade on May 9 when some 3000 LPM members marched from Kuala Lumpur to Kepong, violating regulations and trying to provoke incidents with the police. Participants sang Communist songs, waved red flags, and called upon the people to boycott the general election.
Amidst tensions among the Malay and Chinese population, the general election was held on 10 May 1969. Election day itself passed without any incident and the result shows the Alliance had gained a majority in Parliament at the national level, albeit a reduced one, and in Selangor it had gained the majority by cooperating with the sole independent candidate. The Opposition had tied with the Alliance for control of the Selangor state legislature, a large setback in the polls for the Alliance.
On 12 May, thousands of Chinese marched through Kuala Lumpur and parading through predominantly Malay areas which hurled insults that led to the incident. The largely Chinese opposition Democratic Action Party and Gerakan gained in the elections, and secured a police permit for a victory parade through a fixed route in Kuala Lumpur. However, the rowdy procession deviated from its route and headed through the Malay district of Kampung Baru, jeering at the inhabitants. Some demonstrators carried brooms, later alleged to symbolise the sweeping out of the Malays from Kuala Lumpur, while others chanted slogans about the "sinking" of the Alliance boat — the coalition's logo. The Gerakan party issued an apology on May 13 for their rally goers' behaviour.
In addition, Malay leaders who were angry about the election results used the press to attack their opponents, contributing to raising public anger and tension among the Malay and Chinese communities. On 13 May, members of UMNO Youth gathered in Kuala Lumpur, at the residence of Selangor Dato' Harun Haji Idris in Jalan Raja Muda, and demanded that they too should hold a victory celebration. While , UMNO announced a counter-procession, which would start from the Harun bin Idris' residence. Tunku Abdul Rahman would later call the retaliatory parade "inevitable, as otherwise the party members would be demoralised after the show of strength by the Opposition and the insults that had been thrown at them."
Shortly before the UMNO procession began, the gathering crowd was reportedly informed that Malays on their way to the procession had been attacked by Chinese in Setapak, several miles to the north. Meanwhile, in the Kuala Lumpur area, a Malay army officer was murdered by Chinese hooligans as he and his spouse were coming out from a movie theater in the predominantly chinese area of Bukit Bintang. The angry Malay protestors swiftly wreaked revenge by killing two passing Chinese motorcyclists, and the riot began.
The riot ignited the capital Kuala Lumpur and the surrounding area of Selangor — according to Time, spreading throughout the city in 45 minutes. Many people in Kuala Lumpur were caught in the racial violence—dozens were injured and some killed, houses and cars were burnt and wrecked, but except for minor disturbances in Malacca, Perak, Penang and Singapore, where the populations of Chinese people were similarly larger, the rest of the country remained calm. Although violence did not occur in the rural areas, Time found that ethnic conflict had manifested itself in subtler forms, with Chinese businessmen refusing to make loans available for Malay farmers, or to transport agricultural produce from Malay farmers and fishermen.
Incidents of violence continued to occur in the weeks after May 13, with the targets now not only being Malay or Chinese, but also Indian. It is argued that this showed that "the struggle has become more clearly than ever the Malay extremists' fight for total hegemony."
According to police figures, 196 people died and 149 were wounded. 753 cases of arson were logged and 211 vehicles were destroyed or severely damaged. An estimated 6,000 Kuala Lumpur residents — 90% of them Chinese — were made homeless. Various other casualty figures have been given, with one thesis from a UC Berkeley academic, as well as Time, putting the total dead at ten times the government figure.
In a report from the NOC, the riots was attributed in part to both the Malayan Communist Party and secret societies:
Immediately following the riot, conspiracy theories about the origin of the riots began swirling. Many Chinese blamed the government, claiming it had intentionally planned the attacks beforehand. To bolster their claims, they cited the fact that the potentially dangerous UMNO rally was allowed to go on, even though the city was on edge after two days of opposition rallies. Although UMNO leaders said none of the armed men bused in to the rally belonged to UMNO, the Chinese countered this by arguing that the violence had not spread from Harun Idris' home, but had risen simultaneously in several different areas. The armed Malays were later taken away in army lorries, but according to witnesses, appeared to be "happily jumping into the lorries as the names of various villages were called out by army personnel".
Despite the imposition of a curfew, the Malay soldiers who were allowed to remain on the streets reportedly burned several more Chinese homes. The government denied it was associated with these soldiers and said their actions were not condoned. However, Western observers such as Time suggested that "Whether or not the Malay-controlled police force and emergency government have actually stirred up some of the house-burning, spear-carrying mobs, they seem unwilling to clamp down on them."
In 2007, a book — May 13: Declassified Documents on the Malaysian Riots of 1969 by academic, former Democratic Action Party member and former Member of Parliament Kua Kia Soong — was published by Suaram. Based on newly declassified documents at the Public Records Office in London, the book alleged that contrary to the official account which had blamed the violence on opposition parties, the riot had been intentionally started by the "ascendent state capitalist class" in UMNO as a coup d'etat to topple the Tunku from power.
Immediately after the riot, the government assumed emergency powers and suspended Parliament, which would only reconvene again in 1971. It also suspended the press and established a National Operations Council. The NOC's report on the riots stated, "The Malays who already felt excluded in the country's economic life, now began to feel a threat to their place in the public services," and implied this was a cause of the violence.
Western observers such as Time attributed the racial enmities to a political and economic system which primarily benefited the upper classes:
The riot led to the expulsion of Malay nationalist Mahathir Mohamad from UMNO and propelled him to write his seminal work The Malay Dilemma, in which he posited a solution to Malaysia's racial tensions based on aiding the Malays economically through an affirmative action programme.
Tunku Abdul Rahman resigned as Prime Minister in the ensuing UMNO power struggle, the new perceived 'Malay-ultra' dominated government swiftly moved to placate Malays with the Malaysian New Economic Policy (NEP), enshrining affirmative action policies for the bumiputra (Malays and other indigenous Malaysians). Many of Malaysia's draconian press laws, originally targeting racial incitement, also date from this period. The Constitution (Amendment) Act 1971 named Articles 152, 153, and 181, and also Part III of the Constitution as specially protected, permitting Parliament to pass legislation that would limit dissent with regard to these provisions pertaining to the social contract. (The social contract is essentially a quid pro quo agreement between the Malay and non-Malay citizens of Malaysia; in return for granting the non-Malays citizenship at independence, symbols of Malay authority such as the Malay monarchy became national symbols, and the Malays were granted special economic privileges.) With this new power, Parliament then amended the Sedition Act accordingly. The new restrictions also applied to Members of Parliament, overruling Parliamentary immunity; at the same time, Article 159, which governs Constitutional amendments, was amended to entrench the "sensitive" Constitutional provisions; in addition to the consent of Parliament, any changes to the "sensitive" portions of the Constitution would now have to pass the Conference of Rulers, a body comprising the monarchs of the Malay states. At the same time, the Internal Security Act, which permits detention without trial, was also amended to stress "intercommunal harmony".
Despite the opposition of the DAP and PPP, the Alliance government passed the amendments, having maintained the necessary two-thirds Parliamentary majority. In Britain, the laws were condemned, with The Times of London stating they would "preserve as immutable the feudal system dominating Malay society" by "giving this archaic body of petty constitutional monarchs incredible blocking power"; the move was cast as hypocritical, given that Deputy Prime Minister Tun Abdul Razak had spoken of "the full realisation that important matters must no longer be swept under the carpet...
The state of emergency that was declared shortly after the incident has never been lifted, an action that has been cited by academic lawyers as a reason for diminished civil rights in the country due to the legislative powers granted to the executive during a state of emergency.
Many political analysts attributed the Malay "crutch mentality" syndrome to have arisen from May 13, and a direct result of the affirmative NEP programme. This had resulted to abnormally large proportion of younger generation of Malays not being able to compete not only internationally but also nationally.
Malaysian politicians have often cited the May 13 incident when warning of the potential consequences of racial rhetoric, or as a bogeyman to blanket off discussion on any issues that challenge the status quo. In the 1990 general election and 1999 general election, May 13 was cited in Barisan Nasional campaign advertisements and in speeches by government politicians. Such usage of the incident in political discourse has been criticised; the Tunku stated: "For the PM (Dr Mahathir Mohamad) to repeat the story of the May 13 as a warning of what would have happened if the government had not taken appropriate action is like telling ghost stories to our children to prevent them from being naughty… The tale should not be repeated because it shows us to be politically immature…"
In 2004, during the UMNO general assembly Badruddin Amiruldin , the current deputy permanent chairman, waved a book on May 13 during his speech and stated "No other race has the right to question our privileges, our religion and our leader". He also stated that doing so would be similar to "stirring up a hornet's nest". The next day, Dr Pirdaus Ismail of the UMNO Youth was quoted as saying "Badruddin did not pose the question to all Chinese in the country ... Those who are with us, who hold the same understanding as we do, were not our target. In defending Malay rights, we direct our voice at those who question them." Deputy Internal Security Minister Noh Omar dismissed the remarks as a lesson in history and said that Badruddin was merely reminding the younger generation of the blot on the nation's history.