Gather all ingredients.
Season ribs with salt and pepper.
Pour ½ cup water into the slow cooker, then add ribs. Scatter onion and garlic over top. Cover and cook on Low for 8 hours or High for 4 hours.
When the ribs are almost finished, preheat the oven to 375 degrees F (190 degrees C).
Transfer ribs from the slow cooker to a baking sheet; discard onion and garlic. Coat ribs with barbeque sauce.
Bake ribs in the preheated oven until sauce caramelizes and sticks to meat, 10 to 15 minutes.
