Mainland Scandinavian languages have been reported to allow movement from embedded questions, relative clauses, and complex NPs—domains commonly considered to be islands crosslinguistically. Yet in formal acceptability studies Scandinavian participants often show 'island effects': they reject island-violating movement similarly to native speakers of 'island-sensitive' languages. To investigate this apparent mismatch between informal and formal judgments, we conducted two acceptability judgment experiments testing the acceptability of topicalization from various island domains in Norwegian. We were interested in determining whether we could (i) find evidence for island insensitivity and (ii) pin down the source of qualitatively different island effects. We asked whether such effects are best explained as reflecting violations of a uniform syntactic constraint or extrasyntactic factors. Our results suggest that embedded questions and relative clauses are not uniform syntactic islands for topicalization, but complex NPs are. Unexpectedly, we also found evidence suggesting that conditional adjunct clauses may not be islands.