Preheat the oven to 350 degrees. Line two baking sheets with parchment paper or silicone mats.
Add the flour, baking soda, salt, and pumpkin pie spice to a medium bowl. Stir to combine.
In a mixer bowl, add butter, pumpkin puree, brown sugar, and white sugar. Beat on low speed until combined.
Then, add the egg and vanilla to the mixture and beat until combined.
Slowly add flour mixture to pumpkin mixture and beat until creamy and smooth. Stir in the oats.
Drop batter onto cookie sheets in heaping 1 tbsp. spoonfuls and slightly flatten dough down with your fingers. Leave 1 inch between cookies.
Bake the cookies for about 15 minutes, or until the edges of the cookie are golden brown and the centers are cooked through.
Place the cookies onto a wire rack and allow them to cool before serving.