What is it?
A summary of your employment earnings and deductions for each year.
Your employer Is responsible for providing a copy of this slip to you and ensuring it gets sent to Canada Revenue Agency each year.
Where can I find it?
Your employer should provide you with a copy by the end of February each year. You can also login to 'My Account' through the Canada Revenue Agency website. Your T4 can be found under "tax information slips."