Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream together the softened butter, brown sugar, and white sugar until light and fluffy.
Beat in the eggs one at a time, then mix in the vanilla extract.
In a separate bowl, whisk together the flour, baking soda, cinnamon, and salt.
Gradually add the dry ingredients to the wet mixture, mixing just until combined.
Stir in the oats and raisins until evenly distributed.
Scoop dough into 1 tablespoon-sized balls and place 2 inches apart on prepared baking sheets.
Bake for 8–10 minutes, or until edges are lightly golden and centers are just set.
Allow cookies to cool on the baking sheet for 2 minutes before transferring to a wire rack to cool completely.