De or het volleybalcompetitie?

The correct Dutch article is:

de volleybalcompetitie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use volleybalcompetitie

the volleybalcompetitiede volleybalcompetitie
this volleybalcompetitiedeze volleybalcompetitie
that volleybalcompetitiedie volleybalcompetitie
our volleybalcompetitieonze volleybalcompetitie
your volleybalcompetitiejouw volleybalcompetitie
every volleybalcompetitieelke volleybalcompetitie
which volleybalcompetitie?welke volleybalcompetitie?
a big volleybalcompetitie / the big volleybalcompetitieeen grote volleybalcompetitie, de grote volleybalcompetitie