We use 14-year baseline images obtained with the Wide Field Planetary Camera 2 on board the Hubble Space telescope to derive a proper motion for one of the Milky Way ’ s most distant dwarf spheroidal companions , Leo II , relative to an extragalactic background reference frame . Astrometric measurements are performed in the effective point spread function ( ePSF ) formalism using our own developed code . An astrometric reference grid is defined using 3,224 stars that are members of Leo II that are brighter than magnitude 25 in the F814W band . We identify 17 compact extra-galactic sources , for which we measure a systemic proper motion relative to this stellar reference grid . We derive a proper motion [ \mu _ { \alpha } , \mu _ { \delta } ] = [ +104 \pm 113 , -33 \pm 151 ] \mu as yr ^ { -1 } for Leo II in the heliocentric reference frame . Though marginally detected , the proper motion yields constraints on the orbit of Leo II . Given a distance of d \simeq 230 Kpc and a heliocentric radial velocity v _ { r } = +79 km s ^ { -1 } , and after subtraction of the solar motion , our measurement indicates a total orbital motion v _ { G } = 266.1 \pm 128.7 km s ^ { -1 } in the Galactocentric reference frame , with a radial component v _ { r _ { G } } = 21.5 \pm 4.3 km s ^ { -1 } and tangential component v _ { t _ { G } } =265.2 \pm 129.4 km s ^ { -1 } . The small radial component indicates that Leo II either has a low-eccentricity orbit , or is currently close to perigalacticon or apogalacticon distance . We see evidence for systematic errors in the astrometry of the extragalactic sources which , while close to being point sources , are slightly resolved in the HST images . We argue that more extensive observations at later epochs will be necessary to better constrain the proper motion of Leo II . We provide a detailed catalog of the stellar and extragalactic sources identified in the HST data which should provide a solid early-epoch reference for future astrometric measurements .