Yes — if you attend the Easter Vigil, you normally do not need to attend Easter Sunday Mass, because the Vigil fulfills the Easter Sunday obligation. The Catholic explanation is that attending Mass on the evening before a holy day counts for the obligation, and the Easter Vigil is one of the Masses that satisfies it.

What that means

  • Easter Vigil = counts. Attending it fulfills the Easter duty.
  • Easter Sunday Mass = not required after that. You do not have to go to both.
  • You may still go to Easter Sunday Mass if you want. It is allowed, but it is not required once the obligation has already been met.

Simple rule

If you went to the Easter Vigil, you can skip Easter Sunday Mass and still have fulfilled the obligation.

One caution

If you mean a different church tradition or a local parish rule, practices can vary a little, so if you want absolute certainty for your situation, check with your parish priest.

If you want, I can also give you the Catholic canon-law explanation in plain English.