During her spare time, she occupied herself with antiquarian studies in connection with the work of Geoffrey Chaucer, a medieval English poet and author. She believed that Chaucer's poetic lines could be enjoyed by anyone who had "moderate intelligence and an ear for musical rhythm." As one of his most enthusiastic students, she became a Chaucerian and popularized a number of Chaucer's stories from The Canterbury Tales and some of the shorter poems in anthologies designed for children and for adult non-scholarly readers. She not only provided modernized translations and Pre-Raphaelite illustrations of key scenes from the tales, but also included the type of critical apparatus otherwise only available in the contemporary scholarly editions published by Frederick James Furnivall, Walter W. Skeat, and Richard Morris. Her adaptations played a role in widening general access to Chaucer's poetry and in promoting the reading of Middle English verse in its original.Margaret Connolly, 'Dr Furnival and Mother like the same old books': Mary Haweis and the Experience of Reading Chaucer in the Nineteenth Century, in: Eminent Chaucerians? Early Women Scholars and the History of Reading Chaucer, ed. Richard Utz and Peter Schneck, Philologie im Netz (Supplement 4, 2009), pp. 5–20. She is also the first Chaucerian/art historian to link Chaucer's poetry to existing paintings and drawings.Braswell, Mary Flowers. "The Chaucer Scholarship of Mary Eliza Haweis (1852–1898)." The Chaucer Review, vol. 39 no. 4, 2005, pp. 402–419. Project MUSE, doi:10.1353/cr.2005.0008
