While Helios was also associated with the sun, he was more of a personification of the sun itself, a celestial being who drove the chariot of the sun across the sky each day.

Apollo, on the other hand, was a much more complex and multifaceted god. He was not just the sun god, but also the god of music, poetry, prophecy, healing, plague, archery, and more.

So, while Helios is certainly related to the sun, it's Apollo who is the more widely recognized and iconic sun god in Greek mythology.