| Chen Chien-jen | |
| Native Name Lang: | zh-tw |
| Honorific-Suffix: | MLY |
| Order: | 2nd Representative of Taiwan to the European Union and Belgium |
| Term Start: | August 2004 |
| Term End: | 3 July 2006 |
| President: | Chen Shui-bian |
| Predecessor: | David Lee |
| Successor: | Michael Kau |
| Order1: | 8th Representative of Taiwan to the United States |
| Deputy1: | Lee Ying-yuan Shen Lyu-shun Michael Tsai |
| President1: | Chen Shui-bian |
| Term Start1: | 30 June 2000 |
| Term End1: | 20 May 2004 |
| Predecessor1: | Stephen S.F. Chen |
| Successor1: | David Lee |
| Order2: | 14th Minister of Foreign Affairs |
| Term Start2: | 30 November 1999 |
| Primeminister2: | Vincent Siew |
| Term End2: | 20 May 2000 |
| Predecessor2: | Jason Hu |
| Successor2: | Tien Hung-mao |
| Order3: | 15th Minister of the Government Information Office |
| Term Start3: | 5 February 1998 |
| Term End3: | 30 November 1999 |
| Primeminister3: | Vincent Siew |
| Successor3: | Chao Yi |
| Predecessor3: | David Lee |
| Order4: | Member of the Legislative Yuan |
| Term Start4: | 1 February 1993 |
| Term End4: | 31 January 1996 |
| Constituency4: | Party-list |
| Birth Date: | 1939 8, df=yes |
| Birth Place: | Jiading, Jiangsu, Republic of China |
| Party: | Kuomintang |
| Nationality: | Taiwan |
Chen Chien-jen (; born 11 August 1939) is a Taiwanese diplomat who served as the Foreign Minister from 1999 to 2000.
Chen served in the Legislative Yuan for one term from 1993 to 1996. He was then named the minister of the Government Information Office in 1998. The next year, he was appointed to lead the Ministry of Foreign Affairs. Chen planned to retire after stepping down at the end of President Lee Teng-hui's final term in 2000. However, Lee's successor Chen Shui-bian asked Chen Chien-jen to reconsider. Chen eventually chose to accept the post of representative to the United States.[1] He postponed retirement again in 2004 to become the representative to the European Union and Belgium.[2] Chen was succeeded by Michael Kau in July 2006.[3]
During Hung Hsiu-chu's 2016 presidential campaign, Chen was one of her diplomatic advisers.[4]