Mary Osborn (born in 1940)[4] is a L'Oréal-UNESCO Women in Science Award-winning English cell biologist who, until she stopped running an active laboratory in 2005,[5] was on the scientific staff at the Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.

[5] Mary Osborn and Klaus Weber wrote a classic paper in biochemistry [10] on determination of the molecular weight of a protein via SDS polyacrylamide gel electrophoresis, published in 1969 in Journal of Biological Chemistry.

[4] They knew that in 1967 Shapiro, Vinuela, and Maisel had shown that electrophoresis of proteins along with Sodium Dodecyl Sulfate (SDS) in polyacrylamide gels (PAGE) could separate the tested polypeptide chains by molecular weight.

[6] The results showed convincingly that "the good resolution and the fact that an estimate of the molecular weight can be obtained within a day, together with the small amount of protein needed, makes the method strongly competitive with others commonly employed.

[10] Later, Osborn and Weber pioneered fluorescent antibody staining of cellular substructures, a major technique called indirect immunofluorescence microscopy.

[8][12] Osborn and Weber have pioneered the diagnostic classification of tumor types using specific cytoskeletal elements determined via immunofluorescence microscopy.

[9] When Mary Osborn returned to Europe after years in the US, she was surprised to find that European science, technology, engineering, and mathematics (STEM fields) had not opened doors to women as she had experienced in America.

She was quoted in an article in Science in 1994 to the effect that women's role in Germany was still "kinder, kuche, kirch" (children, kitchen, church.

In an interview in 2004, Osborn said, "In deciding whether to accept new challenges a remark by Diane Britten some years ago in The Times has proved very helpful: "When asked to do something women tend to say `Why me?'