The good Android 21 represents her original self's good side, similar to how Good Buu represents the good aspects of the Innocent Buu. Android 21 is also a rather tall woman, as she is shown to be slightly taller than Gohan. However, she retains the blue eyes of her human form. Her attire changes to a black tube top, keeping the black arm sleeves, and also gaining white baggy pants.

When in her true form, she has pink skin, white hair, her ears become pointed and she gains a tail. Before the split and transformation to her true form, Android 21 (Good) looks identical to her original self: she has auburn hair, wears glasses, a short blue and red checker pattern turtleneck dress with black detached sleeves and a lab coat, and blue and red heels.