Yes! You can! I freeze bell peppers all the time. I would recommend washing, removing the stem and seeds, and slicing or dicing the peppers before freezing. Whenever you have extra peppers from a recipe or one that you are not going to eat before it becomes too ripe, slice it up and put it in a freezer bag or airtight container. Peppers can be frozen for several months. ***Frozen peppers are best if used in cooked dishes as they will not be crisp once frozen and then thawed.