S. exigua may refer to:
Salix exigua, a willow native to North America Scirpus exigua, a spikesedge with a long stem Scopula exigua, a grass moth Selliera exigua, a flowering plant Sertularella exigua, a thecate hydroid Slackia exigua, a gram-positive bacterium Solariella exigua, a sea snail Somena exigua, a Sri Lankan moth Sophora exigua, a plant that releases Sophoraflavanone G into its environment Sphenoptera exigua, a jewel beetle Spodoptera exigua, an owlet moth Stelis exigua, a leach orchid Stenelmis exigua, a riffle beetle Stephanomeria exigua, a plant native to the western United States Synechodes exigua, a little bear moth