Crisp, flaky phyllo dough can be made at home, but it requires a significant degree of skill and patience. Most bakers are content to purchase their phyllo -- also spelled filo or fillo -- in the form of premade sheets. The sheets thaw quickly enough for same-day baking, so you can quickly prepare strudels, spinach pies and other sweet or savory treats whenever the impulse strikes.
Check the frozen-food cases of the stores where you currently buy your groceries. Phyllo is usually located near the pie crusts and puff pastry, in narrow rectangular boxes. If your local grocers don't stock phyllo, larger chain stores -- such as Kroger and Wal-Mart -- almost always do.
Talk to your local baker. Many bakeries use phyllo and order it in bulk, so it's usually not difficult to wheedle a box or two in your hour of need.
Try online stores such as Amazon.com. Type "Filo Dough" or "phyllo dough" in the search box and numerous options will be listed in the returns. A search in Google will reveal many other places that sell phyllo dough in various forms.
Visit or phone any Greek, Mediterranean or Middle Eastern grocers in your area. They'll often have phyllo available in larger sizes or varying thicknesses, and might even offer fresh phyllo rather than frozen.
Store your phyllo according to the manufacturer's instructions. Usually it keeps for up to 2 weeks in your refrigerator, or 9 months to a year in the freezer.