Preheat the oven to 350 degrees. Coat a pie dish with cooking spray.
Combine the flour, oats, brown sugar, and baking soda together in a bowl. Use a pastry cutter to cut in the butter until it resembles a coarse crumbly mixture. Measure 1 cup and set aside. Add the remaining mixture to the pie pan and press firmly to the bottom and sides. Add the raspberry pie filling and smooth out evenly.
Sprinkle the remaining oat mixture on top of the raspberry pie filling then spread evenly.
Place into the oven and bake for 30-35 minutes or until the crumb topping is golden brown.
Let the pie cool for 10-15 minutes before slicing and serving. Enjoy.