Embodiments of the present invention provide an antenna and a communications device. The antenna of the present invention includes a plurality of antenna units. Each antenna unit includes a plurality of antenna branches and one feed branch. Different antenna branches in a same antenna unit correspond to different frequency bands. At least one antenna unit pair exists in the plurality of antenna units. A distance between two antenna units in each antenna unit pair is less than a first preset distance. Radiation directions of antenna branches in each antenna unit pair that correspond to a same frequency band are different. By means of the present invention, isolation between the antenna units in the antenna can be increased.