Preheat your oven to 350°F (175°C). Grease a 9x9-inch baking pan or line it with parchment paper for easy removal.
In a medium bowl, combine the rolled oats, flour, baking soda, and salt. Mix well and set aside.
In a large bowl, beat the softened butter, brown sugar, and granulated sugar together until creamy and smooth.
Add the egg and vanilla extract to the butter mixture, mixing until fully combined.
Gradually add the dry oat mixture to the wet ingredients, stirring until just combined.
Fold in the chocolate chips until evenly distributed throughout the batter.
Spread the batter evenly into the prepared baking pan.
Bake for 20-25 minutes, or until the edges are golden brown and a toothpick inserted in the center comes out clean.
Allow the bars to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely.
Once cooled, cut into squares and serve.