Context : Aims : We report our multiwavelength observations of two homologous circular-ribbon flares ( CRFs ) in active region 11991 on 2014 March 5 , focusing on the transverse oscillations of an extreme-ultraviolet ( EUV ) loop excited by the flares . Methods : The flares were observed in ultraviolet ( UV ) and EUV wavelengths by the Atmospheric Imaging Assembly ( AIA ) on board the Solar Dynamics Observatory ( SDO ) spacecraft . They were also observed in H \alpha line center by the one-meter New Vacuum Solar Telescope ( NVST ) . Soft X-ray ( SXR ) fluxes of the flares in 0.5 - 4 and 1 - 8 Å were recorded by the GOES spacecraft . Results : The transverse oscillations are of fast standing kink-mode . The first-stage oscillation triggered by the C2.8 flare is decayless with lower amplitudes ( 310 - 510 km ) . The periods ( 115 - 118 s ) in different wavelengths are nearly the same , indicating coherent oscillations . The magnetic field of the loop is estimated to be 65 - 78 G. The second-stage oscillation triggered by the M1.0 flare is decaying with larger amplitudes ( 1250 - 1280 km ) . The periods decreases from 117 s in 211 Å to 70 s in 171 Å , implying a decrease of loop length or an implosion after a gradual expansion . The damping time , being 147 - 315 s , increases with the period , so that the values of \tau / P are close to each other in different wavelengths . The thickness of the inhomogeneous layer is estimated to be \sim 0 \aas@@fstack { \prime \prime } 45 under the assumption of resonant absorption . Conclusions : This is the first observation of the excitation of two kink-mode loop oscillations by two sympathetic flares . The results are important for understanding of the excitation of kink oscillations of coronal loops and hence the energy balance in the solar corona . Our findings also validate the prevalence of significantly amplified amplitudes of oscillations by successive drivers .