Calliandra portoricensis (C. portoricensis) is a reputable traditional herbal medicine in Nigeria with long history of use. The parts often use in traditional medicine are leaves and roots. The aim of the present study was to investigate C. portoricensis leaf essential oil (EO) as well as the antioxidant and antimicrobial effects. The EO was obtained by using hydrodistillation technique. Chemical constituents of EO were determined by gas chromatography coupled to mass spectrometry (GC-MS). The antioxidant activity of the EO was evaluated by measuring its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) radical. The antimicrobial activity of Calliandra portoricensis essential oil was assessed employing microdilution method. A total of 39 chemical constituents were identified. The main components identified were monoterpenes (48.05 %) and sesquiterpenes (46.88%). The essential oil showed significant antimicrobial and antioxidant effects.