Brindabellaspis stensioi ("Erik Stensiö's Brindabella Ranges Shield") is a placoderm with a flat, platypus-like snout from the Early Devonian of the Taemas-Wee Jasper reef in Australia. When it was first discovered in 1980, it was originally regarded as a Weejasperaspid acanthothoracid due to anatomical similarities with the other species found at the reef.

According to Philippe Janvier, anatomical similarities of B. stensioi's brain and braincase with those of jawless fish, such as the Osteostraci and the Galeaspida, strongly suggest that B. stensioi, and also the antiarchs, are basal placoderms closest to the ancestral placoderm.

New findings show B. stensioi may have evolutionary traits which connect its morphology to modern or crown-grouped jawed vertebrates, despite its resemblance to ancient jawless fish, showing an instability in the prevailing hypotheses of placoderm evolution.