The 1998 du Maurier Open women's singles was the women's singles event of the one hundred and ninth edition of the Canadian Open; a tournament and the most prestigious women's tennis tournament held in Canada. Monica Seles was the defending champion and won in the final 6–3, 6–2 against Arantxa Sánchez Vicario.
A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated. The top nine seeds received a bye to the second round.