Sirmais (feminine: Sirmā) is a Latvian surname, derived from the Latvian word for "gray" (sirms). Individuals with the surname include: Justs Sirmais (born 1995), Latvian singer Mārtiņš Sirmais (born 1982), Latvian orienteering competitor Zigismunds Sirmais (born 1992), Latvian javelin thrower