The Collaborative International Dictionary of English v.0.48:

nondenominational \nondenominational\ adj.
   not restricted to a particular religious denomination; as, a
   nondenominational school.
   [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

nonsectarian \nonsectarian\ adj.
   not restricted to one sect or school or party; as, religious
   training in a nonsectarian atmosphere; public funding is
   restricted to nonsectarian colleges. Opposite of sectarian.
   [Narrower terms: ecumenic, oecumenic, ecumenical,
   oecumenical; interchurch, interdenominational;
   nondenominational; {undenominational, unsectarian ]
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

nondenominational
    adj 1: not restricted to a particular religious denomination; "a
           nondenominational church"