The school opened enrolment to girls in 1978. Boarding was discontinued in 1980, in order to accommodate more students at St Kilda Road. Wesley first approached Cato College, Elsternwick in the late 1970s regarding amalgamation. Struggling financially, Cato agreed to this in 1986, with integration into Wesley completed by 1989. In November 1989, a fire substantially damaged the St Kilda Road campus. Significant archival material was lost with the virtual destruction of the school library. The damaged areas were rebuilt by 1991.