Maybe. Generally, commission sales people can claim their employment expenses if they were required to pay for them. For other types of employees, if it is stated in your contract that you must provide your own vehicle or pay for some of the work-related expenses, it may be possible. In all cases, a form T2200 Declaration of Conditions of Employment must be filled out by your employer.
For more information on employment expenses, please speak to one of our professionals or visit: http://www.cra-arc.gc.ca/E/pub/tg/t4044/README.html
Another point of interest is that you may be able to get back some of the GST you paid on employment expenses. If you are an employee of a GST registrant and you are deducting expenses from your employment income on your tax return, you can complete form GST370 and include with your return, and you may get a rebate for the GST paid on your expenses.