Arobustneuralnetworkcontroller(NNC)ispresentedfortrackingcontrolofunderwatervehicleswithuncertainties.ThecontrollerisobtainedbyusingbacksteppingtechniqueandLyapunovfunctiondesignincombinationwithneuralnetworkidentification.Modelingerrorsandenvironmentaldisturbancesareconsideredinthemathematicalmodel.Atwo-layerneuralnetworkisintroducedtocompensatethemodelingerrors,whileH∞controlstrategyisusedtoachievetheL2-gainperformance.Theuniformlyultimatelybounded(UUB)stabilitiesoftrackingerrorsandNNweightsareguaranteedthroughtheproposedcontroller.Anon-lineNNweightstuningalgorithmisalsoproposed.Goodperformancesofthetrackingcontrolsystemareillustratedbytheresultsofnumericalsimulations.