Bryde’s whale is the second smallest of the balaenopterid whales. It has a typically elongated shape, and is somewhat less powerfully built than the sei and minke whale, with a body shape generally more like a fin whale. The head is very broad and short with a relatively short, pointed rostrum which is slightly dorso-ventrally flattened. There are two lateral ridges which run from just behind the tip of the snout back as far as the blowholes. They are located between the median line and the outer margin, one each side of the usual balaenopterid median ridge.

There are sometimes a few hairs on the ridges and near the tip of the lower jaw. The eyes are relatively large, compared with those of other balaenopterids. The flippers are small, slender and slightly pointed. The dorsal fin is prominent, pointed and falcate, and up to 46 cm high. It may have a notched or frayed trailing edge. The tail flukes are broad, with a distinct median notch and slightly concave trailing edges. There are about 45 long ventral grooves, which end beyond the umbilicus.