If she had no income, she doesn't have to file, however:
If you are married, it is almost always best to file together as Married Filing Jointly on your federal taxes, even if one spouse has no income. Filing jointly will give you a larger standard deduction and one additional personal exemption, which would otherwise go to waste. Instead, her exemption will offset your income.
I can't speak for each individual state, but the logic is the same.
