1 January – The graphic images on the cigarette packs to show the adverse long-term effects of excessive smoking is introduced.
2 January – Ten persons were killed and five injured in an accident involving three vehicles at Gua Musang Highway near Bukit Sejuk, Gua Musang, Kelantan.
12 January – A rock slide at the Perak Caves Buddhist temple built into a cave killed one person and trapped more than a dozen others for hours near Ipoh, Perak.
23 January – Suspected car thief Kugan Ananthan, aged 22, died five days after being arrested by police in Subang Jaya. Attorney-General Tan Sri Abdul Gani Patail has classified Kugan's death as murder.
These three combo photos show Malaysia's landmark the Petronas Twin Towers in downtown Kuala Lumpur, Malaysia, having their lights turned off (from top to lower ground) to mark Earth Hour on 28 March 2009.
3 March – Three Malaysians among seven people were killed in Hotel blaze in Taipei, Taiwan. A worst fire in 15 years.
3 March – Thousands of people were left trapped and stranded either in buildings, bus stations or light rail transit stations in Kuala Lumpur following flash floods after a heavy downpour since 3pm.
16 March – Limbang district is officially part of Malaysia as Brunei has officially dropped its long-standing claim over Sarawak's Limbang district after the two countries resolved various land and maritime territory disputes.
17 March – MelakaChief Minister, Datuk Seri Wira Mohd Ali Rustam suspended from contesting the post of UMNO deputy president as he was found guilty under Article 10.1 of the UMNO Members Code of Ethics which means that it is deemed that a bribery offence and money politics had been committed by his agents.
16 April – Penang Deputy Chief Minister and state assemblyperson Mohammad Fairus Khairuddin resigns as the state assembly seat of Penanti regarding allegations over his non-performance in public office and corruption allegations
7 May – Perak State Assembly in chaos, Pakatan Rakyat (PR) state Speaker V. Sivakumar removed from the assembly. ex-Sungkai state assemblyman Datuk S. Ganesan took his oath as the new Speaker. Police arrested dozens of protesters, including three opposition MPs, in a standoff near the Perak State Secretariat Building in Ipoh.
26 May – Hunger strike in Perak: All 19 Pakatan Rakyat (PR) assemblymen and supporters arrested earlier Tuesday were released on police bail about five hours later after having had their statements recorded.
31 May – Penanti by-election, 2009, Parti Keadilan Rakyat (PKR) candidate Mansor Othman wins this election with a total majority of 1048 votes beating three independent candidates Aminah Abdullah, Nai-Khan Ari and Kamarul Ramizu Idris.
16 June – The 41-year-old "General" Nor Azami Ahmad Ghazali, leader of the illegal Federal Special Forces of Malaysia (FSFM) and 42 people were arrested in Taman Gombak Jaya, Selangor.
1 July – The KedahDAP decided to quit the Pakatan Rakyat citing "undelivered promises" by the state government as one of the reasons.
8 July – The Cabinet decides that all national primary and secondary schools will teach Science and Mathematics in Bahasa Melayu(Malay Language) and mother tongue for national-type primary schools beginning 2012.
11 July – Najib Tun Razak marks his 100 days as a Prime Minister. He announcing 11 people-friendly measures to all Malaysians – including a toll discount for frequent users and a new trust fund – to address some longstanding public grievances.
14 July – Manek Urai by-election, 2009, PAS candidate Mohd Fauzi Abdullah wins this election with a total majority of 65 votes beating Barisan Nasional (BN) candidates Tuan Aziz Tuan Mat.
14 July – Beginning 1 September, the 20 per cent expressway toll rebate given to motorists who pay toll charges more than 80 times a month, can be saved for up to six months. The rebate can be redeemed at 126 locations which would be announced in due time.
14 July – Malaysia's second micro satellite Razak SAT is launched to orbit.
1 August – Riot police fired water cannons and tear gas, and arrested dozens of demonstrators in the anti-ISA rally in Kuala Lumpur.
9 August – The death toll of the influenza A(H1N1) reached 26 people. The government is considering drastic measures to contain the situation.
9 August – The teaching of Mathematics and Science in English will be extended to 2014. The current cohort of students studying Mathematics and Science in English can continue to do so until they finish their secondary school.
14 August – The death toll of the influenza A(H1N1) reached 56 people.
16 August – A British pilot killed when his plane crashed during takeoff on a test flight in Tekah Airfield, Taiping, Perak.
17 August – The death toll of the influenza A(H1N1) reached 64 people. The government is considering declaring a national health emergency.
23 August – Lunas state assemblyman Mohd Radzhi Salleh quits Parti Keadilan Rakyat (PKR) to become an independent member of the Kedah state legislative assembly.
25 August – Permatang Pasir by-election, 2009, PAS candidate Salleh Man wins this election with a total majority of 4,551 votes beating Barisan Nasional (BN) candidates Rohaizat Othman.
27 August – MCA deputy president, Chua Soi Lek is sacked from the party.
31 August – An express train from Kuala Lumpur to Singapore, carrying 243 passengers, derailed in Batu Enam near Segamat, Johor, injuring 17 passengers including three Singaporeans.
1 September – French "Spider-Man" Alain Robert was arrested after successfully scaling Petronas Towers, in his third attempt on the nation's tallest structure.
8 October – A fire broke out on board of KD Sri Inderapura in Lumut Naval Base, Perak.
11 October – Bagan Pinang by-election, 2009, Barisan Nasional (BN) candidate Tan Sri Mohd Isa Abdul Samad wins this election with a total majority of 5,435 votes beating PAS candidates Zulkefly Mohamad Omar.
19 October – Malaysia Day on 16 September is declared as the annual national public holiday starting 2010 next year.
26 October – About 22 schoolchildren were feared drowned after plunging into a river when a suspension bridge they were crossing collapsed in Kuala Dipang near Kampar, Perak. 19 people safe and three others dead.
29 October – Port Klang state assemblyman Badrul Hisham Abdullah quits Parti Keadilan Rakyat (PKR) with immediate effect to become an independent representative supporting the Barisan Nasional (BN).
1 November – Former Perlis mufti Dr Mohd Asri Zainul Abidin is arrested by the Selangor Religious Affairs Department (JAIS) officials late last night as he was conducting a religious class.
4 November – Kelantan received the "Wang Ehsan" compassionate payment from the federal government from the state's offshore oil production revenue starting next year.
16 November – The Kota Siputeh state seat in Kedah is declared vacated by the High Court..
18 November – Former Perlis mufti Dr Mohd Asri Zainul Abidin claimed trial at the Gombak Timur Lower Syariah Court, Selangor to a charge of teaching aspects related to Islam without certification early this month.
24 November – The body of the political secretary of Seri Kembangan state assemblyman Ean Yong Hian Wah, Teoh Beng Hock is laid to rest for the second time, three days after his remains were exhumed for a second autopsy at Sungai Buloh Hospital.
25 November – The Selangor state government issued a ban prohibiting state civil servants, employees of state subsidiaries, and students at state-owned institutions from attending the National Civics Bureau or "Biro Tata Negara" (BTN) courses.
29 November – A powerful explosion ripped through a mamak restaurant in Stulang, near Johor Bahru, Johor, jolting dozens of nearby residents from their sleep. No one was injured in the incident, which was believed to have been caused by a powerful bomb made of plastic explosives.
6 December – Two nursing students at a private college here were killed and four others injured when a car plunged from the third-floor car park of the KB Mall shopping complex and landed on the shopping area in Kota Bharu, Kelantan.
10 December – Former Port Klang Authority (PKA) general manager Datin Paduka O.C. Phang claimed trial at the Klang Sessions Court to three counts of CBT amounting to a total of RM254mil over the Port Klang Free Zone (PKFZ) scandal.
14 December – A gas explosion at the soon-to-be-opened RM288 million AEON Bandaraya Melaka Shopping Centre in Jalan Lagenda, in Bachang, Melaka, killed a contractor and injured more than 20 others, including six critically.
26 December – Ten passengers were killed and two injured after a double-decker Sani Express bus skidded and hit the road divider at Km 272.8 of the North-South Expressway as it was heading north, about 8 km from the Ipoh South toll plaza near Ipoh, Perak.
27 December – Beginning 1 January 2010, the minimum price of cigarettes will be RM6.40 for a 20-stick pack when the Health Ministry enforces the minimum cigarette and prohibition of price promotion through the Control of Tobacco Products Regulation (Amendment) (No.2) 2009.
31 December – The High Court declared that the Herald can use "Allah" in its Catholic weekly publication and that the Home Minister order banning its use is illegal, null and void.
Malaysia was only formed on September 16, 1963. Prior to that date, Peninsular Malaysia was known as Malaya when it was a British protectorate before independence.