Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.
In a large bowl, cream together the softened butter, granulated sugar, and light brown sugar until light and fluffy, about 3-4 minutes.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In a separate bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the semisweet chocolate chips evenly into the dough.
Using a tablespoon or cookie scoop, drop rounded balls of dough about 2 inches apart onto the prepared baking sheets.
Bake in the preheated oven for 10-12 minutes, or until the edges are set but the centers still look slightly soft.
Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.