The first of the new buses will begin operating on GO's Highway 407 routes on Thursday and the remaining vehicles sometime before the end of May.
The province's inter-regional transit system services the Greater Toronto and Hamilton Area, with routes connecting to the Greater Golden Horseshoe region.
"By adding more GO buses, we are providing commuters with more travel options and making it easier for them to get ot work, school or appointments," Transportation Minister Glen Murray said in a statement.
According the Ontario government, the new vehicles will be able to carry 26 more passengers each, and because they are lower than GO's current double-deckers, also able to run on 34 additional routes.
Earlier this week, Metrolinx, the provincial transportation agency, tabled a shortlist of potential funding tools to help pay for transit expansion projects planned for the Greater Toronto and Hamilton area.