A by-election for the Kyoto-3rd seat in the Japanese House of Representatives was held on 24 April 2016, coinciding with the by-election in Hokkaido. The seat became vacant after sitting member Kensuke Miyazaki resigned on 12 February 2016 in the midst of an extramarital affair scandal. Miyazaki, a member of the Liberal Democratic Party, served the district from 2012. He defeated Democratic Party MP Kenta Izumi by slim margins in the 2012 (0.1%) and 2014 (2.7%) elections.
Izumi managed to wrest back his old seat by a landslide, eclipsing his nearest rival by 45 percentage points.
The district had 344,696 registered voters for the election, an increase of 0.12% since the 2014 general election. As the voting age for national elections was decreased to 18 years in June 2016, this by-election, along with the Hokkaido by-election, were the last national-level election with a minimum voting age of 20 years. The by-elections were the first national-level elections contested by the Democratic Party, Initiatives from Osaka party and Party for Japanese Kokoro under their respective current names. The Communist Party also chose not to field a candidate in the election, despite receiving 27,000 votes (16%) in the 2014 election.
The by-election was a six-way race. The LDP decided against fielding a candidate due to the perceived anti-LDP sentiment in light of the Miyazaki scandal. Party bosses were also worried that a heavy defeat in Kyoto might affect LDP's campaign for the House of Councillors election in summer.
<small>Note:<br /> <sup>1</sup> The percentage swing for the Democratic Party candidate is calculated based on the vote share obtained by its predecessor, DPJ.<br /> <sup>2</sup> The percentage swing for the Initiatives from Osaka candidate is calculated based on the vote share obtained by its predecessor, Japan Innovation Party.</small>