Before you start

Social Insurance Number
T4 slips from employers
Records of foreign income and foreign property
A determination of the date you became a tax resident

Step-by-step

1
Establish the date you became a tax resident
Canadian tax residency turns on residential ties — a home, a spouse, dependants, then secondary ties such as bank accounts and a driving licence — rather than on a day count. Your first return covers only the part of the year after that date, and getting the date right shapes everything downstream.
OnlineWho: You
2
File one return by 30 April, covering both governments
Ontario tax is calculated on the federal return and collected by the CRA. Certified software is free for most situations and free volunteer clinics exist for modest incomes, which many newcomers qualify for in their first year. File even for a short part-year, because the assessed return is what triggers the GST/HST credit and the Canada Child Benefit.
OnlineWho: YouBy 30 April
3
Read the property tax bill as three levies, not one
If you buy, the bill you receive from the City of Mississauga contains a City portion, a Region of Peel portion and a provincially set education portion. People compare 'Mississauga's tax rate' against another municipality's without noticing they are comparing different combinations. Compare the total, on a comparable assessed value.
OnlineWho: You
4
Expect the stormwater charge somewhere you are not looking for it
Mississauga funds its stormwater system through a separate user charge based on the hard surface area of the property, and it appears on the Region of Peel water bill rather than on the property tax bill. Owners routinely fail to find it and assume it is missing. It is not a tax, and it is not on the tax bill.
OnlineWho: You
5
Report foreign property above the threshold on form T1135
Residents holding specified foreign property costing more than CAD 100,000 in total must file this each year. Penalties for non-filing are severe and applied per year, and a property you still own abroad is the usual trigger.
OnlineWho: You
6
Register for CRA My Account once you have filed
This is where tax slips, benefit payments and refunds live. Registration requires information from a filed return, so most newcomers complete it after the first filing rather than before.
OnlineWho: You

Documents you’ll need

Social Insurance Number
T4 and other information slips
Records of foreign income, accounts and property
Property tax and water bills, if you own
Receipts for medical expenses, childcare and tuition

Things most newcomers don’t know

There is no tax reason to choose Mississauga over Toronto, and people keep looking for one.

Income tax is federal plus provincial and identical across Ontario. HST is 13% everywhere in the province. The only municipal levers are property tax and municipal land transfer tax — and on the latter Mississauga does have a genuine edge, because Toronto levies its own municipal land transfer tax on top of the provincial one and Mississauga does not. That difference applies when you buy, not when you earn.

Source: Canada Revenue Agency — Ontario tax rates

The stormwater charge is on the water bill, from a different government.

The City funds stormwater through a dedicated user charge calculated from the hard surface on a property, and bills it through the Region of Peel's water bill rather than through property tax. New homeowners look for it on the tax bill, do not find it, and assume they are not paying it. It is also the reason a large paved driveway costs more per year than a small one.

Source: City of Mississauga — stormwater charge

File a part-year return even if you earned almost nothing.

The assessed return is what starts the benefit machinery — the GST/HST credit, the Canada Child Benefit, the Ontario trillium benefit. Newcomers who arrive in October reasonably conclude there is no point filing for three months of income, and then wonder for a year why no benefit payments arrive. The return is the trigger, not the income.

Source: CRA — Newcomers to Canada

Residency for tax is about ties, not about 183 days.

The 183-day rule is the most confidently repeated wrong answer in Canadian tax. Residency is determined by residential ties: a home available to you, a spouse or dependants here, then secondary ties. Someone who arrives in November with a lease, a family and a job is a resident from November regardless of the day count, and someone who spends 200 days here without ties may not be.

Source: CRA — determining residency status

Common mistakes to avoid

Skipping the first part-year return and forfeiting the benefit entitlements it triggers.
Assuming a 183-day rule determines when you became a tax resident.
Comparing municipal property tax rates without adding the Region and education portions.
Looking for the stormwater charge on the property tax bill, where it is not.
Missing form T1135 on foreign property costing more than CAD 100,000.
Expecting an Ontario municipality to offer an income tax advantage. None does.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.

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