By-elections for the Ninth Legislative Yuan were held in 2019, two on 27 January and four on 16 March, at Taiwan to elect 6 of the 113 members of the Legislative Yuan for the remaining term until 2020.

The by-election was the result of resignations by Pasuya Yao, Democratic Progressive Party legislator for Taipei 2;[1] Kuomintang legislator Lu Shiow-yen from Taichung 5;[2] Wang Huei-mei, Kuomintang legislator for Changhua County 1; Huang Wei-cher, Democratic Progressive Party legislator for Tainan 2; and Yang Cheng-wu, Kuomintang legislator for Kinmen County.

Under the Article 73 of the Civil Servants Election And Recall Act [zh], if any positions become vacant due to resignation or election to another office, and the vacated term is longer than one year, a by-election shall be completed within three months commencing from the date of resignation.

[3] On 30 November 2018, the Central Election Commission announced that by-elections for Taipei 2 and Taichung 5 were to be held on 26 January 2019.

[4] On 4 December 2018, the CEC moved the date to 27 January 2019, as the previously announced date coincided with the General Scholastic Ability Test.