Line your 9×9 inch baking dish with parchment paper, leaving some overhang on the edges.
In a mixing bowl, combine the rolled oats, peanut butter, honey, and vanilla extract. Mix well using a spatula until the ingredients are thoroughly combined and form a sticky dough.
Transfer the mixture into the lined baking dish. Use the spatula or your hands to press it down firmly and evenly.
In a microwave-safe bowl, combine the dark chocolate chips and coconut oil. Microwave in 30-second intervals, stirring after each, until the chocolate is fully melted and smooth.
Once melted, pour the chocolate over the pressed oat mixture, spreading it evenly with a spatula.
Place the baking dish in the refrigerator for at least 1-2 hours, or until the chocolate has hardened and the mixture has set.
Once set, lift the bars out of the dish using the parchment overhang. Cut into squares or rectangles.
Your No-Bake Peanut Butter Chocolate Oatmeal Bars are ready to be enjoyed.