An electronic device may be provided with wireless circuitry. The wireless circuitry may include multiple antennas and transceiver circuitry. The antennas may include antenna structures at opposing first and second ends of the electronic device. The antenna structures at a given end of the device may include antenna structures that are shared between multiple antennas. The electronic device may include a first antenna with an inverted-F antenna resonating element formed from portions of a peripheral conductive housing structure and may have an antenna ground that is separated from the antenna resonating element by a gap. A return path may bridge the gap. The electronic device may also include a second antenna that includes the antenna ground and an additional antenna resonating element. The antenna resonating element of the second antenna may be parasitically coupled to the return path of the inverted-F antenna at given frequencies.