Not necessarily. Ontario’s tax system is progressive, which means only the portion of your income that falls into a higher bracket is taxed at a higher rate. If your income rises modestly due to inflation or cost-of-living adjustments, indexed brackets may actually prevent you from paying more tax than before.
However, higher-income earners may still see an increase in overall tax payable due to Ontario’s surtaxes and the Alternative Minimum Tax, which significantly raise effective tax rates at higher income levels.

Ontario’s income tax brackets, rates, surtaxes, and non-refundable credits apply starting January 1, 2026, and will be reflected when you file your 2026 tax return in spring 2027.
Most refundable benefits, including the Ontario Trillium Benefit, Ontario Child Benefit, and GAINS, apply for the benefit period from July 1, 2026, to June 30, 2027, and are typically paid monthly during that period.

In most cases, no separate application is required, but you need to fill in the correct information when you file your annual tax return, Ontario automatically assesses your eligibility for provincial credits and benefits based on your income, family status, and residency.
To ensure you receive all benefits you are entitled to, it is important to file your tax return on time each year, even if you had little or no income during the year.