Yes, you can. You can retrieve up to three years to request a retroactive payment from the Canadian Revenue Agency under a program known as the taxpayer relief provision. For example, if you have not filed your 2018 or 2019 tax returns within a three year period, you can file the written request for retroactive payments with the CRA. However, you must file your taxes for the previous year to qualify. For example, if you did not complete your 2019 taxes, you must file those to claim retroactive payments for 2020. And keep in mind that you only have three years from either end of the tax year to file an income tax return to claim a tax refund or the date of the original notice of assessment to request an adjustment to an assessment issued for a previous tax year.