Preheat oven to 350°F (175°C). Line a baking sheet with parchment paper.
Whisk together flour, baking soda, salt, and cinnamon in a medium bowl.
Beat butter, brown sugar, and granulated sugar until creamy, about 2-3 minutes.
Add eggs one at a time, beating well after each. Stir in vanilla extract.
Gradually mix dry ingredients into wet mixture, stirring until just combined.
Fold in oats and butterscotch chips evenly into the dough.
Scoop tablespoon-sized portions of dough and place on the baking sheet, spacing 2 inches apart.
Bake for 10-12 minutes until edges are golden and centers are soft. Let cool on the sheet for 5 minutes before transferring to a wire rack.