Margaret Olrog Stoddart was born at Diamond Harbour, Canterbury. She was educated in Edinburgh, then studied at Canterbury School of Art. As a young woman, Margaret spent much of her time on the family farm in the Chatham Islands.

Stoddart exhibited with the Canterbury Society of Arts from 1883 and with other New Zealand Societies from 1884. From 1885 she was on the Council of the Canterbury Society of Artists. In the late 1890's she went to England and studied in Cornwall under the American artists Charles Laszel. From 1901-02 she was strongly influenced by the Newlyn School.

Stoddart returned to New Zealand around 1907 exhibiting at the Royal Academy and the Paris Salon. She taught at the Canterbury Society of Arts and was a leading member of the art community in Christchurch until her death in 1934.

In 1928 the Canterbury Society of Arts held an exhibition of her 'Past and Present'. She is best known for her watercolours of flowers, many of them in her favourite blues and whites and her watercolours of river beds.