[yarddog]

It is technically illegal not to file but if you owe nothing it will usually not be prosecuted.

[Col Frank Slade]

I FORGOT

[HiTech RedNeck]

There is a failure to file penalty calculated on taxes owed. The penalty is nothing if no taxes are owed.

[AntiScumbag]

It is technically illegal not to file but if you owe nothing it will usually not be prosecuted.

Nonsense.

Fact: If you have no tax liability for any given year it is entirely legal not to file a return. You cannot be penalized or prosecuted for failing to file a return you were not required to file.

One might file a return for a year during which you had no taxable income because you had loss carry-forwards, or for many other reasons.

Typical FR tax and financial illiteracy. Do NOT seek tax advice on this site. Or any other.