Preheat your oven to 350°F (175°C). Line a baking sheet with parchment paper or grease it lightly.
In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon. Set aside.
In a large mixing bowl, cream together the softened butter, brown sugar, and granulated sugar using an electric mixer or a whisk until light and fluffy.
Add the egg and vanilla extract to the butter mixture, and mix until well combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Stir in the rolled oats and chocolate chips until evenly distributed.
Using a cookie scoop or spoon, drop rounded tablespoons of the dough onto the prepared baking sheet, spacing them about 2 inches apart.
Bake in the preheated oven for 10 to 12 minutes or until the edges are lightly golden.
Remove from the oven and let the cookies cool on the baking sheet for about 5 minutes before transferring them to a cooling rack to cool completely.