Dorothy Bush Koch (born August 18, 1959), sometimes called "Doro", is the younger sister and youngest sibling of George W. Bush, the 43rd President of the United States. Her four siblings are George W. Bush, Jeb Bush, Marvin Bush, and Neil Bush. She is also the younger daughter and youngest child of former President of the United States George H.W. Bush and former First Lady Barbara Bush.

In 1975, during a visit to Beijing, (it is said) she became the first person publicly baptized in China since its communist government began discouraging foreign religious practices in 1949. She has served as a Pioneer fundraiser for her brother's presidential campaigns.

She has two children by her first husband, William LeBlonde, and two children by her second husband, Robert Koch of Koch Industries.