General elections were held in Thailand on 14 May 2023 to elect 500 members of the House of Representatives. The Move Forward Party, led by Pita Limjaroenrat, surprised analysts by winning the most seats, followed by fellow opposition party Pheu Thai who had won the most seats in the 2011 and 2019 elections. Turnout was a record 75.22%.
The elections were held using a parallel voting system as in the 1997 and 2007 constitutions, in contrast to the mixed-member apportionment system used in 2019. Like in 2019, the elected prime minister did not need to be a member of the House and would be chosen by the full National Assembly, including the 250 military-appointed members of the Senate, for a total 376 seat majority. Due to the structure of the National Assembly, experts had warned of a possible gridlock scenario in which the current opposition parties secure more than half of the House votes but are obstructed in the Senate. Additionally, the Election Commission had received criticism over untrustworthiness, unprofessionalism, and bias in its conducting of the voting process.
Sixty-seven parties vied for seats. The ruling conservative coalition government was composed of the major Palang Pracharath, Bhumjai Thai, and Democrat parties, and smaller parties including the new United Thai Nation Party, who nominated former junta leader and incumbent prime minister Prayut Chan-o-cha after his split with Palang Pracharath. The pro-democratic opposition was led by the Pheu Thai and Move Forward parties, the latter being the effective successor of the dissolved Future Forward Party, which had performed unexpectedly well in the 2019 election. Political campaigns focused on the Thai economy, especially its recovery from the COVID-19 pandemic. Some parties, most notably Move Forward, also highlighted progressive issues, and challenged long-held social norms in Thailand.
Pita's Move Forward initially formed a coalition with the other pro-democracy, anti-military parties, which had a majority in the lower house but was unable to form a government after being functionally blocked by allies of the monarchy and military in the Senate. Pheu Thai then assumed the lead, dissolving its alliance with Move Forward and allying instead with conservative, pro-military parties. It then nominated real estate tycoon Srettha Thavisin as prime minister. He was elected by Parliament on 22 August. 
On August 7, 2024, Thailand's Constitutional Court banned the victors of the election, the Move Forward Party and all of its leaders from politics for its proposal to reform the lèse-majesté law, arguing it posed a threat to the constitutional order.
Background.
Following a political crisis in Thailand, the military staged a coup d'état in 2014, ousting the civilian caretaker government of Yingluck Shinawatra. The military junta, known as the National Council for Peace and Order (NCPO), rose to power under the leadership of former army chief Prayut Chan-o-cha as Prime Minister. In 2016, the NCPO completed the drafting of a new constitution and held a referendum to approve it. They banned criticism of the draft constitution and prohibited monitoring of the referendum. Activists against the document were arrested, detained, and prosecuted in military courts, whilst voters who expressed their intention to vote against the draft were also arrested and prosecuted by the military regime.
In 2019, after numerous delays, the junta finally held a general election on 24 March. The elections were seen as a skewed race in which Prayut had an unfair advantage, with the Senate wholly appointed by the junta and the constituencies redrawn last-minute. After the election, the pro-junta Palang Pracharath party formed a coalition government, with Prayut selected by the parliament for another term as prime minister even though his party did not win the most seats.
Prayut began his second term as prime minister on 9 June 2019. According to the current constitution, a prime minister can only serve for a maximum of eight years. However, the end of Prayut's term as the prime minister of Thailand is disputed since there are many interpretations about the beginning of his term. On 30 September 2022, the Constitutional Court finally ruled that Prayut's term began in 2017 along with the new constitution, meaning that he may serve as the prime minister until 2025, if he is selected by the parliament again.
The 2020–2021 nationwide protests started as demonstrations against the premiership of Prayuth but later expanded to include numerous long-overlooked issues in Thai society, and unprecedented demands to reform the monarchy. The Thai royal family is protected by a lèse-majesté law. Even though the protests largely died down due to crackdown, repression, and COVID-19 restrictions, it was anticipated that activism could resurge in this election and afterwards. 
The end of 2022 saw the split in the ruling Palang Pracharath Party between Prayut and his close associate Prawit Wongsuwon, after the latter showed accommodation towards the main opposition Pheu Thai Party. Prayut was expected to join the new United Thai Nation Party along with his loyalists in the Palang Pracharath Party. Forty politicians, including 34 incumbent MPs from both coalition and opposition camps, also resigned from their parties to join Bhumjai Thai Party to increase their winning chances in this election. On 23 December 2022, Prayut announced his intention to apply for membership of the United Thai Nation Party, as well as becoming the party's sole prime ministerial candidate.
Rumor of a possible coup was circulated long before the election. In September 2022, a cabinet minister, Chaiwut Thanakamanusorn, warned that protesting may result in the cancellation of the election.
Electoral system.
Unlike the preceding 2019 election, which used a form of mixed-member proportional representation with 350 constituency seats and the remaining 150 being levelling seats, the electoral system was changed in a 2021 amendment of the constitution which restored the pre-2017 parallel voting system and removed the proportional representation mechanism.
Of the 500 members of the House of Representatives to be elected, 400 seats were elected from single-member constituencies by first-past-the-post voting (an increase of 50), and 100 party-list seats—filled separately and no longer serving as leveling seats—are voted on in a separate ballot (unlike in the 2019 election, where only one vote was cast by each voter to determine both constituency and levelling seats). The change was criticised by smaller parties as the system benefits larger parties—especially the ruling Palang Pracharath Party and the main opposition party Pheu Thai, who both supported the amendment—at the expense of smaller ones, including the progressive Move Forward Party, whose predecessor Future Forward performed successfully in 2019 thanks to the proportional representation system.
Prime ministerial candidates.
The process of selecting a prime minister is still the same as the preceding 2019 election under the 2017 Thai constitution. Prime ministers may only be chosen from a pre-declared list of candidates. Each party may submit up to three names and must have at least 25 members in the House of Representatives to receive eligibility. Candidates do not have to be a member of parliament (MP).
Parliament's vote for prime minister will take place in a joint session with the 250-seat Senate appointed by the junta, according to the constitution's provisional terms. In 2019, all the senators unanimously voted for then-junta leader Prayut. As the term of the NCPO-appointed Senate lasts until 2024, it is expected to exert influence into this election as well.
Due to this rule, the anti-junta camp had to secure at least 376 votes in order to select their candidates, while a simple majority in the House could still result in a candidate from the pro-junta coalition winning the selection. If no candidates secured at least 376 votes in the Parliament, it could lead to a deadlock and pave the way for a person not in the parties' list of candidates becoming prime minister as written in the Constitution. Such a scenario led some to call for strategic voting for larger anti-junta parties most likely to win in each constituency.
2022 reapportionment and redistricting.
Due to the increase of the number of members of the House of Representatives elected from single-member constituencies from 350 to 400, a reapportionment of seats and redrawing of electoral boundaries was required. On 1 February 2022, the Election Commission announced its calculations that, from the total registered population of 66,171,439 as of 31 December 2021, there must be 1 member per 165,429 people. This distribution is subject to the approval of the organic law bills currently being considered by the National Assembly.
The provisional number of members of the House of Representatives to be elected from single-member constituencies in each province are as follows:
The Election Commission had just finished drawing electoral boundaries in February 2023—just three months before the election, while many candidates had already begun campaigning. The original drawing was challenged in the Constitutional Court as the Commission included non-citizens in the calculation. The Court struck down the drawing, prompting the Commission to revise and present another boundary drawing. The second drawing was also challenged in the administrative courts amid the accusation of gerrymandering by the Commission, but the court eventually ruled the drawing was legal in April 2023.
Leading up to the election.
Since late 2022, ex-politician Chuwit Kamolvisit began attacking Prayut whose relative was allegedly linked to Chinese nationals involving drug, gambling and money laundering. He later turned to Bhumjai Thai Party, accusing it of corruption regarding Orange Line rapid transit planning and promoting unrestricted use of marijuana.
In January 2023, two youth political activists began a hunger strike calling for the release of political prisoners detained before trial. Many of them were charged with lèse-majesté, which led to another debate on amending or cancellation of the law. Political parties were asked for their stance on the issue.
Beginning in January 2023, many civil society organizations called for volunteers to keep their eyes on the election process, citing the untrustworthiness of the Election Commission and its decision not to report the election result in real-time. As of March 2023, the movement had grown to 50 organizations, including media, who declared they would report the unofficial election result when the Commission would not.
On 20 March 2023, the House of Representatives was dissolved—three days before the term ended. Due to a legal technicality, the election date was postponed for another week from 7 May 2023. The move also allowed politicians more time to switch parties, which many analysts interpreted as the real motive behind it. Some commentators also noticed that the election day was set during the period of university exams and after a long holiday which could make voting inconvenient for a lot of Thais who have to return to vote in their constituencies.
In March 2023, a group of hackers posted the personal data of 55 million Thais for sale online. The group called 9Near with a symbol resembling that of the Move Forward Party, also mentioned on their page: "Almost election, choose wisely."
In May, ex-prime minister Thaksin Shinawatra tweeted that he was ready to return to Thailand before July 2023 and "enter the legal process". He faced possible prison time from prior convictions.
The Thai economy was still recovering from the COVID-19 pandemic, but it was still struggling with multiple issues, including high energy and electricity costs, the number of employers still fewer than before the pandemic, rising household debts, and falling income growth. Other economic issues such as minimum wage, farm subsidies, and welfare were considered top voting issues. Most political parties campaigned on subsidies and tax exemptions.
Contesting parties.
A total of 67 political parties applied to participate in the elections by party list system, of which 49 party numbers are selected by lottery and then in order of the application period.
Overseas and advanced voting.
More than 2 million Thais registered for advance voting, while other 100,000 people registered to vote from overseas. Thailand's Ministry of Foreign Affairs reported that around 80% of the eligible overseas voters had done so. Even with high temperatures, some districts still expected a 90% turnout.
The Election Commission's conduct of advance voting drew sharp criticism from the public, especially from numerous cases of incorrect information on ballot envelops. Chuvit Kamolvisit also pointed out irregularities in some Northeastern provinces where unusually high number of voters voted in advance and there were reports of collection of ID cards. More than a million people also signed an online petition to oust the Election Commission.
Results.
Final results were announced on 25 May. The Election Commission endorsed all 500 MPs on 20 June; 67 parties won seats. While there were media reports that 71 MPs-elect in 37 constituencies received election fraud complaints,