Is Parsley Annual?

I have planted flat leaf parsley and it is growing very busy. Now since fall has arrived I need to know whether I should remove them and take them indoors or is it a perennial?

Parsley is a hardy biennial. It is hardy to USDA zone 6. That means that if you are in zone 6 or higher, your parsley should winter over. You can check the hardiness zone maps in the InfoCentre section of the Richters website for the zone for your area. If your zone is 5 or less then you will need to keep the plants indoors over winter.
Although parsley is biennial, it goes to flower in the second year and sets seeds, and does little else. That is why it is normally grown as an annual, even though it will survive the winter. Still, even in the second year with the mostly flowering stems and relatively few usable leaves, it is still worth hanging on to your plants for spring and early summer use.