2009 in Thailand

Typhoon Ketsana, known in the Philippines as Tropical Storm Ondoy, was the second-most devastating tropical cyclone of the 2009 Pacific typhoon season, causing $1.15 billion in damages and 665 fatalities, only behind Morakot earlier in the season, which caused 956 deaths and damages worth $6.2 billion. Ketsana was the sixteenth tropical storm, and the eighth typhoon of the season. It was the most devastating tropical cyclone to hit Manila, surpassing Typhoon Patsy (Yoling) in 1970.

Miss Thailand Universe 2009, the tenth Miss Universe Thailand pageant held at Sofitel Centara Grand Bangkok, in Bangkok, Thailand on 28 March 2009. The contestants arrived at Ko Samui, Surat Thani a week earlier to do activities before coming back to Bangkok for rehearsals.

The ninth gubernatorial election for the city of Bangkok, Thailand was held on 11 January 2009. The election came about after the resignation of Apirak Kosayothin on 13 November 2008, the incumbent who was only just re-elected a little more than a month (on 5 October 2008). the resignation stemmed from an indictment by the National Counter Corruption Commission or NCCC, in which Apirak was indicted for the controversial 6.6 billion Baht fire-engine procurement contract. The former Prime Minister and former Bangkok Governor Samak Sundaravej was also found guilty in the same verdict. On 13 November Apirak announced his resignation saying: "Like the Democrat Party, I support a move that will perpetuate politics-for-people" at the same time maintaining his innocence and stating that his resignation should become an example of a change in Thai politics, his resignation triggered an automatic by-election. By the end of the 11 January 2009, Sukhumband was declared the winner of the race, becoming the 15th Governor of Bangkok.

The Santika Club fire was a fireworks accident and nightclub fire that occurred on Thursday 1 January 2009, in the Santika Club in Ekkamai, Watthana, Bangkok, where New Year celebrations were taking place. 67 people were killed and another 222 injured when fire swept through the club during the New Year's celebration as the band "Burn" was playing.

Sao Saw Et (Thai: เสาร์ซาวเอ็ด, lit: Saturday the 21st, in Northern Thai) was an incident of discrimination against LGBT people in Chiang Mai, Thailand, consisting of hate speech and violent attempts to stop the 2009 Pride Parade which was scheduled to take place there on 21 February 2009, ultimately leading to its cancellation. It is considered an important event in Thai LGBT history and was compared to the Stonewall Riots in the US. The date, 21 February, has been annually observed as the day against violence against LGBT in Thailand amongst activists.

By-elections were held in Thailand on 11 January 2009. The elections were held to fill 26 vacant parliamentary seats. elected by the first past the post voting system.

Bangkok Airways Flight 266 was a scheduled domestic passenger flight from Krabi Airport to Samui Airport, Thailand. On 4 August 2009, the aircraft skidded off the runway on landing and crashed into an old and unmanned control tower. One pilot died and 41 other people were injured.

The Fourth East Asia Summit was held in Cha-am and Hua Hin, Thailand on October 23-25, 2009. The East Asia Summit (EAS) is a pan-Asia forum held annually by the leaders of 16 countries in the East Asian region. EAS meetings are held after annual ASEAN leaders' meetings. The Fourth East Asia Summit was rescheduled several times, had its venue changed and one attempt to hold it was cancelled due to the 2008–2009 Thai political crisis. It was finally held on October 25, 2009.