Place the salad greens in a medium bowl. Combine the lemon juice, honey, mustard, and olive oil in a jar with a tight-fitting lid. Shake until well combined. Alternatively, place the lemon juice, honey, and mustard in a bowl. Whisk to combine. Add olive oil in a slow, steady stream until dressing is emulsified.
Drizzle the honey-mustard dressing over the mixed greens. Toss to combine. Taste and adjust for seasoning with salt and pepper.