For many years coastal barrier studies have focused on the classification of coastal regions into variants of the classical transgressive or regressive models. However, there are many situations which are not adequately represented by existing models, requiring a fuller range of descriptions of coastal depositional systems. This paper describes a ‘composite’ transgressive‐regressive barrier system at Minninup, southwestern Australia, which differs substantially in morphology, stratigraphy and evolution from the published barrier models. The Minninup barrier is geomorphically characterised by isolated back‐barrier flats and channels, a broad, transgressive dune field, narrow foredune, reflective beach, and narrow and shallow nearshore zone. Stratigraphically, the mid‐ to late Holocene sandy barrier sediments are perched on top of muddy back‐barrier facies. Mid‐Holocene sea‐level rise to approximately + 3 m above present sea‐level initiated development of raised beach and nearshore units. Heavy‐mineral concentration has taken place along this section of coast throughout the development of the barrier and is preserved in all units. Comparison of the Minninup barrier with other transgressive systems reveals significant variations in terms of setting, stratigraphy, morphology and evolution. Most notable are the extremely thin shore‐normal width of the barrier, preservation of elevated mid‐Holocene deposits, and the erosion‐resistant and very low gradient transgressed substrate. Studies carried out at Minninup improve our knowledge of barrier evolution through the identification of morphostratigraphic patterns different to those used in classical models.