Sadie Lea Weidner (March 3, 1875 – December 24, 1939) was an American missionary to Japan.

She began her professional career as a teacher and taught in an elementary school for a period of five years.

[2] When she came to Japan for the first time in June 1900, she was assigned as a school teacher and missionary in Sendai City, Miyagi Prefecture.

During a brief visit to USA in 1907, she went to different local churches in order to mobilize support for Miyagi Girls' School and the mission activity in Japan.

Meanwhile, in 1909, she learned courses on language, and school system and its legal aspects at Columbia University.