The "10 minute or better" service will cost the city about $11 million, and should be in place by the end of the year, TTC chair Josh Colle said at a news conference at Bathurst Station.
Colle said the plan, which was already approved in the 2015 operating budget, will enact the 10-minute standard seven days a week between 6 a.m. and 1 a.m.
"That means that TTC riders will have shorter wait times at transit stops," he said. "It'll help to decrease crowding on vehicles and provide a more comfortable, convenient but most importantly reliable service for our users."
Nine of the routes already meet the 10-minute standard, meaning that 42 routes across the city are having their service expanded.
Colle said he can't guarantee TTC vehicles will never be late, but said the standard requires a significant investment in vehicles and employees, gives the commission a number to be held too, and makes the service "consistently more reliable."
TTC deputy CEO Chris Upfold said he expects the changes to increase fare revenue by about $4 million.
He said the service expansion makes part of the TTC a "turn-up-and-go service" meant to give riders confidence that they don't have to plan.
The service announcement comes a week after a power outage and a failure of a backup power supply caused a crippling subway shutdown during morning rush hour. Colle said the announcement was made only because the specific routes are about to come before the commission.