小犬座属于现代八十八现代星座，也是托勒密48星座之一。据说象征着猎户座的猎犬之一，另一条猎犬是大犬座。小犬座包含中国古代的南河、水位星座。

是一个小星座，有两颗重要的星。南河三（小犬座α星，英文Procyon），星等为0.38。南河二小犬座β星，英文Gomeisa），星等为2.9。南河三是全天第8亮的星，英文和希腊文中的意思是“前哨狗”，因其在天狼星之前升起之故。

Canis Minor /ˌkeɪnᵻs ˈmaɪnər/ is a small constellation in the northern celestial hemisphere. In the second century, it was included as an asterism, or pattern, of two stars in Ptolemy's 48 constellations, and it is counted among the 88 modern constellations. Its name is Latin for "lesser dog", in contrast to Canis Major, the "greater dog"; both figures are commonly represented as following the constellation of Orion the hunter.