Altus Lacy Quaintance (December 19, 1870 – August 7, 1958) was an American entomologist who specialized in the study of insect pests of fruit trees.

He was recognized as an expert on Aleyrodidae, a family of white flies that are major pests of citrus and greenhouse plants.

In 1903, he was hired at the US Bureau of Entomology and later became entomologist in charge of the new Division of Deciduous Fruit Insect Investigations, responsible for research on insect pests of fruit trees, a function that he retained until his retirement in 1930.

[1] After his retirement, Quaintance settled on his farm, called "Quaint Acres", in 1940 in Maryland where he propagated fruit and ornamental nursery stock.

[1] Quaintance was a charter member of the Entomological Society of America, served as president of the Entomological Society of Washington,[3] and was elected president of the American Association of Economic Entomologists in 1904.