In a large bowl, combine the cannellini beans, kidney beans, chickpeas, red bell pepper, red onion, and parsley.
In a small bowl, whisk together the lemon juice, olive oil, salt, and pepper.
Pour the dressing over the bean mixture and toss to combine.
Refrigerate for at least 1 hour before serving to allow the flavors to meld together.
Serve chilled and enjoy!