This paper aims to assess the role of multi-word compound adverbs in distinguishing Brazilian Portuguese (PT-BR) from European Portuguese (PT-PT). For this study, a large lexicon of Portuguese multi-word adverbs (3,665) was annotated with diatopic information regarding language variety, which has not been available so far. The paper then investigates the distribution of this category in the DSL (Dialect and Similar Language) corpus of journalistic texts, representing Brazilian (PT-BR) and European Portuguese (PT-PT). Results indicate a substantial similarity between the two varieties, with a considerable overlap in the lexicon of multiword adverbs. Additionally, specific adverbs unique to each language variety were identified. Lexical entries recognized in the corpus represent 18.2% (PT-BR) to 19.5% (PT-PT) of the lexicon, and approximately 5,700 matches in each partition. While many of the matches are spurious due to ambiguity with otherwise nonidiomatic, free strings, occurrences of adverbs marked as exclusive to one variety in texts from the other variety are rare.