It is a lowland forest species, occurring from sea level to 1,000 m and occasionally recorded to 1,500 m, and is also found in gallery forest in savanna (Coates 1985, Beehler and Pratt 2016). Although the species's tolerance of logged forest is uncertain, it has been recorded from degraded forest edge (G. Dutson in litt. 2016). It feeds on birds, rodents and insects (Pratt and Beehler 2015).

Uroglaux dimorpha is sparsely but widely distributed in New Guinea (Papua, formerly Irian Jaya, Indonesia and Papua New Guinea). In the 1980s and 1990s there had only been records from nine sites, including a series of individuals caught near Lae, Papua New Guinea (Hicks 1988, Lamonthe 1993, Shany 1995, K. D. Bishop in litt. 1999, P. Gregory in litt. 1999, T. Leary in litt. 2000, C. Makamet per B. Beehler in litt. 2000). There has, however, been a recent increase in records (related to the availability of sound-recordings); it is now known from about 20 localities (Beehler and Pratt 2016) and eBird records (eBird 2017) suggest it may be at many more sites than this.