A wet-mateable electrical connector comprises a vertically movable female connector unit 52 locatable over a vertically fixed male connector unit 50. The female connector unit 52 defines a chamber 62 containing a gas to exclude water and the like therefrom and having a closed upper end and an open lower end for receiving an upper end of the male connector unit 50. An insulating sheath 6 is locatable within the upper end of the female connector unit 52 to move it from a first position that protects a first electrical contactor 4 provided on the upper end of the male connector unit 50 to a second position that exposes the first electrical contactor 4. The upper end of the female connector unit 52 houses a second electrical contactor 3 which is engageable with the first electrical contactor 4 upon movement of the insulating sheath 6 from the first position to the second position.