Iris Shun-Ru Chang (traditional Chinese: 張純如; March 28, 1968 – November 9, 2004) was an American journalist, historian, and political activist. She is best known for her best-selling 1997 account of the Nanjing Massacre, The Rape of Nanking, and in 2003, The Chinese in America: A Narrative History. Chang is the subject of the 2007 biography Finding Iris Chang, and the 2007 documentary film Iris Chang: The Rape of Nanking starring Olivia Cheng as Iris Chang. The independent 2007 documentary film Nanking was based on her work and dedicated to her memory.

Chang was born in Princeton, New Jersey, to a Taiwanese American family, as the daughter of university professors Ying-Ying Chang, (Chinese: 張盈盈; born 1940) and Shau-Jin Chang (Chinese: 張紹進; January 7, 1937 – January 25, 2025). Ying-Ying was born in Chongqing to parents originally from Guiyang, while Shau-Jin was born in Suqian. Both spent their early childhood in Chongqing, the capital of China at the time, due to the Second Sino-Japanese War on the eastern coast, with Ying-Ying's family having fled Nanjing from the invading Imperial Japanese Army three years before her birth. Chang's parents separately emigrated to Taiwan in 1949 and 1951 respectively, moving to the United States in 1962 after receiving scholarships at Harvard University.

Chang's English name was chosen to invoke both the Greek rainbow goddess Iris as well as the iris of the eye, while her Chinese name meant "something pure and innocent". She was born two weeks overdue and lived the first months of her life in housing provided by Princeton Hospital. In late 1969, after briefly living in Boulder, Colorado, for a physics workshop, the family relocated to Champaign–Urbana, Illinois, where her father had accepted a teaching position at the University of Illinois. Chang grew up hearing stories about the Nanjing massacre, from which her maternal grandparents escaped. When she tried finding books about the subject in the Champaign Public Library, she found there were none.

Chang attended the University Laboratory High School of Urbana, Illinois, and graduated in 1985. She was initially a computer science major, but switched to journalism, earning a bachelor's degree at the University of Illinois at Urbana-Champaign in 1989. During her time in college she also worked as a New York Times stringer from Urbana-Champaign, and wrote six front-page articles over the course of one year. After brief stints at the Associated Press and the Chicago Tribune, she pursued a master's degree in Writing Seminars at Johns Hopkins University. She began her career as an author and lectured and wrote magazine articles.

In 1991, Chang married Bretton Lee Douglas, a design engineer for Cisco Systems, whom she had met in college, and had one son, Christopher, who was two years old at the time of her suicide. She lived in San Jose, California, in the final years of her life.

Chang wrote three books documenting the experiences of Chinese and Chinese Americans in history. Her first, Thread of the Silkworm (Basic Books, 1995) tells the life story of the Chinese professor, Qian Xuesen (or Tsien Hsue-shen) during the Red Scare in the 1950s. Although Qian was one of the founders of NASA's Jet Propulsion Laboratory (JPL), and for many years helped the military of the United States debrief scientists from Nazi Germany, he was suddenly accused of being a spy and a member of the Communist Party USA, and was placed under house arrest from 1950 to 1955. Qian left for the People's Republic of China in September 1955. Upon his return to China, Qian developed the Dongfeng missile program, and later the Silkworm missile, which was used by the Iraqi military during its war on Iran and against the United States-led coalitions during the Persian Gulf War and the 2003 invasion of Iraq.

Her second book, The Rape of Nanking: The Forgotten Holocaust of World War II (1997), was published on the 60th anniversary of the Nanjing Massacre and was motivated in part by her own grandparents' stories about their escape from the massacre. It documents atrocities committed against the Chinese by forces of the Imperial Japanese Army during the Second Sino-Japanese War, and includes interviews with victims. The Rape of Nanking remained on the New York Times Bestseller list for 10 weeks. Based on the book, an American documentary film, Nanking, was released in 2007.

After publication of the book, Chang campaigned to persuade the Japanese government to apologize for its troops' wartime conduct and to pay compensation.