Jeannette "Jenny" Hermine Kastein (24 January 1913 – 20 October 2000) was a Dutch breaststroke swimmer.
She won a silver medal in the 200 m breaststroke at the 1931 European Championships, behind Cecelia Wolstenholme.
Next year she set four world records in the 400 m and 500 m breastroke (unofficial events), but could not compete in the Olympics due to the overall financial problems related to the Great Depression.
She won the national titles in the 200 m in 1933, 1935 and 1936, yet her performance declined, and at the 1936 Summer Olympics she finished in a mere seventh place.In 1942, Kastein married Evert Heleonardus Scheijde, a physician; they had two sons.