Margaret B. Denning (October 17, 1856 – August 16, 1935) was an American missionary and temperance worker who spent 29 years in India.

[3] She was stationed at Gonda, United Provinces, where she became active in temperance work in connection with her mission enterprises.

[1] In 1911, Denning was elected president of the National Woman's Christian Temperance Union (W.C.T.U.)

For some years preceding her election as president, she had been corresponding secretary of the Union, which at that time had a membership of about 4,000.

[2] Besides delivering frequent addresses, Denning wrote a number of temperance pamphlets, as well as a book entitled Mosaics from India.