Marilyn Fleer FASSA is an Australian professor of early childhood education and development at Monash University in Melbourne, Australia.

[2] Fleer grew up in Narrikup, Western Australia, a rural farming community.

[5] Fleer's research is focused on early childhood "concept formation", in particular the developmental meaning of conceptual play.

Her work has especially focused on how young children learn science, technology, engineering, and mathematics concepts through play.

[2][6][7] She was elected Fellow of the Academy of the Social Sciences in Australia in November 2021.