Micromyrtus grandis (better known as the Severn River heath-myrtle) is a shrub in the myrtle family. It is found exclusively in the Severn River Nature Preserve and a property next to it, located around 60 km north-west of Glen Innes (Australia). It grows up to 1–4 metres tall, making it the largest plant in the genus Micromyrtus. The Severn River heath-myrtle is characterized by its fruit, which is 5-ribbed, and its broader leaves when compared to other nearby flora.