Smaragdus (, Smaragdos) is a Latin masculine given name of ultimately Semitic origin, meaning "emerald". It may refer to:
Saint Smaragdus (d. c. 303), Roman Christian martyr, companion of Cyriacus Saint Smaragdus (d. 320), one of the Forty Martyrs of Sebaste Smaragdus (fl. 585–611), Byzantine administrator Ardo Smaragdus (died 843), hagiographer Smaragdus of Saint-Mihiel (d. c. 840), Benedictine monk
See also Smaragdis