Prime Minister Hun Sen's Cambodian People's Party (CPP) won all the seats in the 125-member National Assembly (see note) in the absence of participation by viable opposition parties, following a ban of the only significant opposition party. According to the National Election Committee, voter turnout was 83 per cent – a figure contested by the opposition.

The 2018 elections followed intensifying tensions between the government and the major opposition party – the Cambodia National Rescue Party (CNRP) – which had won 55 seats in the 2013 elections. The Government and the CNRP then signed an agreement and CNRP members, including the then CNRP leader, Mr. Sam Rainsy, were sworn into the National Assembly in July 2014.

However, the rivalry revived as the National Assembly suddenly stripped Mr. Rainsy of his parliamentary mandate (following a court order for his arrest on a 2008 defamation conviction). In July 2017, the National Assembly approved additional amendments to the Law on Political Parties, which further restricted freedom of association and expression. The law effectively required the CNRP to sever all ties with its former leader, ahead of parliamentary elections scheduled for July 2018. In November 2017, the Supreme Court dissolved the CNRP. It also banned 118 CNRP leaders (including all 55 CNRP members of the National Assembly) from political life for five years with no possibility of appeal. Their parliamentary mandates were immediately revoked and their seats reallocated to non-elected political parties allegedly aligned with the ruling party. The Supreme Court decision was based on charges of conspiracy with a foreign country to overthrow the legitimate government brought against the president of the CNRP, Mr. Kem Sokha. Most of the former CNRP MPs have gone into exile. Mr. Sokha has remained in jail since September 2017. He has denied the charges.

Mr. Rainsy (in exile since 2015) called for a boycott of the 2018 elections. CNRP vice president, Ms. Mu Sochua (who also lives in exile), called the new members of parliament illegitimate.

Note:
The statutory number of National Assembly members has increased from 123 to 125 due to an increase in the number of seats allocated to Preah Sihanouk province.