What name do I put on my Canadian tax forms?

Say my name is Jane Doe and I married John Smith last year. I haven't legally changed my name to Jane Smith on my drivers license or anything other form of id. So my question is when filling out my taxes do I put Mrs.Jane Doe, Mrs.Jane Smith or Ms.Jane Doe?

This is simple...The tax dept doesn't care what your name is, it is the Social insurance number (S.I.N.) that they go by

On the front of the tax form is a place to indicate marital status, Check the appropriate box
Enter the first name and Social Insurance number of your spouse.

For your name...USE WHATEVER NAME YOU WANT TO USE NOW, OR INTO THE FUTURE.

I do not use my full first name, only my usual usage and middle initial, and full last name

you have to figure out what last mame you want to use for tax purposes and keep with it, any working place should list your last name the same, as T-4 slips will use that name.

It's true, your name doesn't seem to bother CRA, they'll take anything.

My wife worked before marrying, so her SIN is in her maiden name. Her T-4s come in her married name (never formally legally changed), and she has other ID (including her passport)in a variation on her maiden name (she is French Catholic, so they tend to write names in a different order). Nobody has any issue with this, it seems, they understand it's all the same person.

Oh, and nobody but you cares if you use Ms or Mrs, it's up to you. So you can be Ms Jane Smith as well. Or even Ms Jane Doe-Smith if you want.

Except in Quebec, where you are Mlle. Jane Doe, no matter what!