The acquisition of the Danish sound system can be a difficult task for both native and non-native speakers. This paper is an attempt at showing the ways in which /r/ contributes to the system's overall complexity. It is suggested that /r/-related difficulties in Danish are due to the impact /r/ has on the neighboring sounds and, as a result, on the relations between graphemes, phonemes and sounds. Several phenomena connected with the presence of /r/ in various contexts are presented to exemplify the above statement, including r-coloring (i.e. the change of the quality of the neighboring vowel), the fusion of /r/ with neighboring vowels and the interactions between /r/ and /ə/, resulting in a change of vowel length and/or the assimilation of [ə]. The analysis focuses mainly on the grapheme-sound relations and the ways /r/ affects the discrepancy between Danish orthography and pronunciation.