In a large mixing bowl, combine the black beans, kidney beans, and chickpeas.

Add the chopped bell pepper, red onion, and celery to the bowl with the beans.

In a separate bowl, whisk together the olive oil, apple cider vinegar, Dijon mustard, honey, salt, and black pepper.

Pour the dressing over the bean and vegetable mixture and toss gently to combine. Serve immediately or refrigerate for an hour to let the flavors meld.