A paint brush cover has a bottom opening; a stretchable, breathable, moisture-wicking fabric body with an internal volume less than a volume of an inserted paint brush head; and a top opening narrower than the fabric body and the paint brush head and sized to freely admit the brush handle. A paint brush is inserted handle-first through the bottom opening until the wider brush head registers in a fully covered position with the brush head stretching the fabric body into moisture-wicking contact against the bristles, and with the bristle ends spaced above the bottom opening. The bottom opening may be stiffened with a flexible stiffener that flexes open when a brush head is inserted, or with a closure flap.