In a large bowl, toss the chicken in the buttermilk. Cover and refrigerate for 1 hour.
Meanwhile, in a medium bowl, combine the mayonnaise, mustard and honey.
Heat a grill to medium-high and lightly brush with oil. Drain the chicken tenders; pat dry and season with salt and pepper. Grill, turning once, until cooked through, about 5 minutes. Serve with the honey-mustard dipping sauce.