We report the discovery of seven strongly lensed Lyman break galaxy ( LBG ) candidates at z \sim 7 detected in Hubble Space Telescope ( HST ) Wide Field Camera 3 ( WFC3 ) imaging of Abell 1703 . The brightest candidate , called A1703-zD1 , has an observed ( lensed ) magnitude of 24.0 AB ( 26 \sigma ) in the WFC3/IR F160W band , making it 0.2 magnitudes brighter than the z _ { 850 } -dropout candidate recently reported behind the Bullet Cluster and 0.7 magnitudes brighter than the previously brightest known z \sim 7.6 galaxy , A1689-zD1 . With a cluster magnification of \sim 9 , this source has an intrinsic magnitude of H _ { 160 } = 26.4 AB , a strong z _ { 850 } - J _ { 125 } break of 1.7 magnitudes , and a photometric redshift of z \sim 6.7 . Additionally , we find six other bright LBG candidates with H _ { 160 } band magnitudes of 24.9 - 26.4 , photometric redshifts z \sim 6.4 - 8.8 , and magnifications \mu \sim 3 - 40 . Stellar population fits to the ACS , WFC3/IR , and Spitzer /IRAC data for A1703-zD1 and A1703-zD4 yield stellar masses ( 0.7 - 3.0 ) \times 10 ^ { 9 } M _ { \sun } , stellar ages 5 - 180 Myr , and star-formation rates \sim 7.8 M _ { \sun } yr ^ { -1 } , and low reddening with A _ { V } \leq 0.7 . The source-plane reconstruction of the exceptionally bright candidate A1703-zD1 exhibits an extended structure , spanning \sim 4 kpc in the z \sim 6.7 source plane , and shows three resolved star-forming knots of radius r \sim 0.4 kpc .