Elections to the House of Councillors of Japan were held on 20 July 2025, with 124 of the 248 members of the upper house of the National Diet to be elected for a term of six years.

The election took place about 10 months into the premiership of Shigeru Ishiba, who governed Japan as Prime Minister after he won the leadership of the ruling Liberal Democratic Party (LDP) in September 2024. Shortly after he became Prime Minister, Ishiba announced snap elections to the House of Representatives for 27 October, which saw the LDP lose its majority for the first time since 2009. Since November 2024, Ishiba governed as the leader of a minority government, struggling to pass legislation and budget agreements without the support of opposition parties. Growing dissatisfaction with the LDP and a scandal involving gift vouchers given to MPs by Ishiba had hurt his approval ratings. Simultaneously, opposition parties had attempted to unite in an effort to deny the LDP a majority in the election; the Constitutional Democratic Party (CDP) and Ishin no Kai Party in particular formulated plans to hold "opposition primaries" in several prefectures. The 17-day campaign began on 3 July, with 518 total candidates running. Measures to combat the rising cost of living and immigration were the key issues of the election.

Similar to the outcome of the 2024 general election, the ruling coalition of the LDP and Komeito lost its majority in the House of Councillors. The LDP’s national vote share fell to 21.6%, the lowest result in the party’s history. The coalition’s decline was driven by growing support for smaller opposition parties. Parties making major gains included the center-right Democratic Party for the People, which displaced Komeito to become the third-largest party in the chamber and fourth-largest in the Diet overall, and the right-wing populist Sanseitō, whose anti-immigrant rhetoric drew significant media attention during the campaign period. In addition, a record number of women won seats in the Diet. Following the election, Ishiba faced calls to resign from some members within his party. He announced his intention to resign as party president in September 2025, triggering a snap leadership election to replace him in October.

These were the last Japanese upper house elections held before the official translation of its name was changed from "House of Councillors" to "Senate"; the Japanese name of the upper house, Sangiin (参議院), was unchanged.

Electoral system Elections to the House of Councillors are held every three years. Councillors serve six-year terms and half of the house is elected in each election. The councillors up for election in 2025 were last elected in 2019.

Similar to the House of Representatives, elections for the House of Councillors are contested via mixed-member majoritarian representation. In this parallel voting 74 of the 124 councillors up in this election were elected in single-member or multi-member districts corresponding to the prefectures of Japan using first-past-the-post (FPTP) voting in the single-member districts and the single non-transferable vote (SNTV) system in the multi-member prefectural districts. The remaining 50 councillors were elected in a single nationwide district using open-list party proportional representation via the D'Hondt method. Each prefectural district elects at least one councillor each election, meaning each district has at least two councillors in total. The number of councillors allotted to each prefectural district is based on population; for example, Tokyo has a total of twelve councillors, with six being elected each election. It should also be noted that certain prefectures are "combined" into one to correct the disparity in the value of one vote. Since 2016, Tottori and Shimane Prefectures and Tokushima and Kochi Prefectures, respectively, have been combined into single electoral districts. Although voters may cast preference votes for specific candidates in the proportional election, since 2018, parties may prioritize certain candidates to receive allocated seats ahead of their most-voted candidates. There is no electoral threshold that parties must meet to be allocated seats in the proportional component.

Political parties

Parties Leader Ideology Seats Status Last election Before election Liberal Democratic Party Shigeru Ishiba Constitutional Democratic Party of Japan Yoshihiko Noda Liberalism rowspan="1" Komeito Tetsuo Saito Buddhist democracySocial conservatism Japan Innovation Party Hirofumi YoshimuraSeiji Maehara Right-wing populismEconomic liberalism rowspan="6" Japanese Communist Party Tomoko Tamura CommunismDemocratic socialism Democratic Party For the People Yuichiro Tamaki Conservatism Reiwa Shinsengumi Tarō Yamamoto Progressivism Left-wing populism Collaborative Party(also known as the NHK Party) Ayaka Otsu Right-wing populism Social Democratic Party Mizuho Fukushima   Okinawa Social Mass Party Tetsumi Takara rowspan="2" Sanseitō Sohei Kamiya

Background

Previous election The October 2024 general election resulted in the loss of majority of the Liberal Democratic Party-Komeito governing coalition in the House of Representatives under Prime Minister Shigeru Ishiba, with the possibility of the ruling coalition suffering another "major defeat" at the House of Councillors election if opposition parties unite their candidates.

Multi-party cooperation Opposition unification attempts According to Jiji Press, if five opposition parties, including the main opposition Constitutional Democratic Party of Japan (CDP), make deals in the 32 single-seat constituencies, the ruling LDP-Komeito coalition is projected to win 10 seats against the opposition camp's 22, and only three if the Nippon Ishin no Kai, also known as the Japan Innovation Party, joins the opposition alliance.

In January 2025 Ishin introduced a plan to the CDP that would seek to "unify" the opposition in single-member districts against the LDP; their proposal involves the use of online polls and holding primary elections. Reiwa, the Social Democratic Party, and the Democratic Party For the People (DPP) cast doubt on the plan while the Communists declined to participate entirely.

Later in February, Ishin announced that a decision on whether or not to hold opposition primaries would be made within the month; party Secretary General Ryohei Iwatani commented that every party except the Communist Party had been "quite positive" about the plan. He also said the party was open to reforms to their plan by the CDP.

In early March, Ishin co-leader Seiji Maehara proposed running a primary system with the CDP in the prefectures of Shiga, Nara and Wakayama (1 seat each) for election; all of them were in the area of influence of Osaka, Ishin's stronghold.

Speaking on the prospect of uniting the opposition CDP leader Yoshihiko Noda stated "I generally support the plan, but I have told Maehara that we need the participation of all opposition parties, so we should make an appeal for them to participate, and that if the only opposition candidates in a constituency are from the Constitutional Democratic Party and the Japan Innovation Party [Ishin], then we should settle it through a primary election."

On 1 April, Ichirō Ozawa announced an agreement between the CDP and Ishin no Kai to have an unified single candidate in Shiga, Nara and Wakayama Prefectures.

On 6 March, the DPP began working on a policy agreement with the CDP. In March, the Mainichi Shimbun reported that the CDP and DPP were expected to sign a basic policy agreement ahead of the election that would likely cover the Constitution, foreign policy and security, economy, energy, and diversity.

Sankei Shimbun reported in early April that cooperation between the CDP and DPP cooperation was in doubt ahead of the election, with the former viewing the latter as an insincere "cocky upstart," while the DPP viewed CDP members as not garnering support because it "only cares about elections." The two parties continued to struggle with election cooperation.

CDP leader Noda said on 10 May that there is a "great possibility" that a general election could be held either on the same day or around the same time of the upper house election.

LDP-Komeito alliance The ruling LDP signed an agreement with the Komeito (their coalition partner since 2012) in February regarding cooperation in the election, which stated that the LDP would support Komeito candidates in five districts and set conditions for Komeito support of those implicated in the slush fund scandal.

At the LDP’s party convention on 9 March, Ishiba said the party should aim to unify and return to its roots of “people-friendly politics.” The day earlier Ishiba stated he wanted to “win at all costs.”

Ishiba’s former leadership rival Takayuki Kobayashi criticized Ishiba’s speech, claiming he did not get a sense of a string message from the Prime Minister; others believed the part’s minority status in the Diet hurt the LDP, and Ishiba's efforts to shape the country’s national agenda. Sanae Takaichi, also a former LDP leadership rival, was critical of Ishiba's speech as well.

Kobayashi would later advise the party to assess Ishiba's presidential election manifesto & the party's previous general election manifesto ahead of the summer upper house election, arguing that the party should check on progress.

On the same day as Ishiba's speech, Mio Sugita was revealed as an endorsed candidate for proportional representation in the election. In 2022 and 2023, Sugita had been found guilty of human rights violations by the Sapporo Legal Affairs Bureau for posting discriminatory statements against ethnic Koreans, LGBT people and others on her blog. Sugita's remarks, for which she apologized, were largely considered to be racist.

The Asahi Shimbun reported that the LDP's decision to endorse the controversial former lawmaker was likely due to requests from the conservative wing of the faction close to the late Prime Minister Shinzo Abe, whom Sugita was said to be close to.

On 11 April 2025, LDP Chief Advisor Tarō Asō described the election situation as an "emergency" for the LDP, and stated that the ruling parties had to maintain their majority in the upper house.

The Komeito published a draft manifesto centered around lowering gas prices and getting rid of provisional gas taxes. Regarding tariffs imposed by the United States, Chief Representative Tetsuo Saito argued that "the most effective [economic response] would be a tax cut," and said that a cash handout should be distributed in the meantime until tax cuts are implemented so as to provide relief to citizens.

Mainichi reported that the coalition could only afford to lose 16 seats to avoid losing their majority in the upper house.

Government reactions and low approval ratings Prime Minister Ishiba's cabinet has faced consistently low approval ratings since taking office in October 2024, succeeding former Prime Minister Fumio Kishida who had also suffered from sub-20% approval ratings in July 2025, saw the rise of LDP rebels and Sanseito known as the "Summer of Discontent".

Meanwhile, the low approval ratings and the government's situation in the election put immense pressure on the ruling coalition (LDP and Komeito). Having already lost their majority in the lower house election in October 2024, the July 20 upper house election was a crucial test for Ishiba's leadership. Failing to secure the necessary 50 seats to maintain a majority in the House of Councillors could intensify calls for his resignation.

The party reportedly gained support from those who had supported the LDP during Shinzo Abe's incumbency, but were strongly dissatisfied with the succeeding prime ministers. The sudden growth of the party was dubbed the "Eye of the storm".

Other developments