Rachel Lloyd (January 26, 1839 – March 7, 1900) was an American chemist best known for her work on the chemistry and agriculture of sugar beets (Beta vulgaris).
She studied at the Harvard Summer School before receiving her doctorate from the University of Zurich in 1886, becoming the first American female to earn a doctorate of chemistry and only the second woman in the world to receive a doctorate in her field, after Julia Lermontova..
Lloyd spent many years teaching chemistry and holding other positions at various educational institutions before and after her work in Nebraska.
In 1891, she became the first regularly admitted female member of the American Chemical Society.
More than a century later, the Society designated her research and professional contributions to chemistry a National Historic Chemical Landmark on October 1, 2014, at the University of Nebraska–Lincoln.