赛氏豆丁海马（学名：Hippocampus severnsi），又名豆丁海马、小闽豆丁，为海龙科海马(鱼)属下的一个种。

Severn’s pygmy seahorse (Hippocampus severnsi) is one of the smallest known seahorses, reaching a maximum adult size of just 1.3 cm. It is usually dark brown in colour with a large red patch covering its shoulder. This species is known from Southeast Asia and the Pacific Islands. Sightings of the seahorse in the Philippines was first confirmed in 2014.