Stebbing was educated at James Allen's Girls' School, Dulwich, until she went, in 1904, to Girton College, Cambridge, to read history (though Cambridge did not award degrees or full University membership to women at the time). Having come across F. H. Bradley's "Appearance and Reality" she became interested in philosophy and stayed on to take part I of the Moral Sciences tripos in 1908. This was followed by a University of London M.A. in philosophy in 1912 that was awarded with distinction. Her thesis for the same, "Pragmatism and French Voluntarism", subsequently being published in the Girton College Studies series.