Su Tseng-chang (Chinese: 蘇貞昌; pinyin: Sū Zhēnchāng; Pe̍h-ōe-jī: So͘ Cheng-chhiong; born 28 July 1948) is a Taiwanese politician who served as premier of the Republic of China (Taiwan) from 2006 to 2007 and again from 2019 to 2023.

Su eventually teamed with Hsieh as the vice presidential nominee; the DPP lost to the Kuomintang ticket of Ma Ying-jeou and Vincent Siew.

[4] During the Chen administration, Su, along with politicians Annette Lu, Frank Hsieh and Yu Shyi-kun, are collectively known as the "Big Four of the Democratic Progressive Party".

[12] Su's subsequent reelection occurred by a wide margin despite the ability of the Pan-Blue Coalition to present a united candidate, Wang Chien-shien.

[10] Following DPP losses in the 2005 municipal elections on December 3, Su announced that he would, pursuant to a pre-election promise, resign from the chairmanship.

[16] Su faced calls for his resignation after the Rebar Chinese Bank run, but refused to leave his post at the time.

[23] Su also stated that he previously submitted resignations numerous times over his sixteen-month tenure, but all were rejected by President Chen.

[35] He succeeded William Lai, who had resigned in response to the Democratic Progressive Party's poor performance in the 2018 Taiwanese local elections.

[36] Su and his second cabinet resigned en masse following the 2020 Taiwanese legislative election, as stipulated in the constitution, but Tsai, who won reelection to the presidency, asked him to remain in his post.

[39] On January 19, 2023, Su announced his resignation as Premier as part of a reshuffle following the DPP's heavy defeat in the 2022 Taiwanese local elections.