As　a　new　artificial　sweetener　(ASs),　the　jeopardize　of　neotame　(NEO)　to　aquatic　environment　is　attracting　concern　due　to　its　widespread　usage　and　difficulty　in　removing　from　wastewater.　UV/periodate　(UV/PI)　is　being　considered　as　an　effective　process　for　the　degradation　of　micropollutants　in　wastewater.　However,　there　are　few　studies　of　the　roles　of　reactive　species　(RS)　and　the　effects　of　complex　water　matrices　on　the　degradation　of　NEO　via　UV/PI.　The　degradation　of　NEO　in　aqueous　media　by　UV/PI　was　investigated　herein.　NEO　was　effectively　removed　(＞97　%)　by　UV/PI　within　4　min.　The　degradation　of　NEO　was　mainly　attributed　to　•OH　(75.7　%),　IO3•　(23.0　%)　and　1O2　(1.3　%)　with　the　observed　second-order　rate　constants　of　7.71　×　109,　1.56　×　108　and　2.94　×　105　M−1　s−1,　respectively.　The　contribution　of　IO3•　and　1O2　to　NEO　degradation　was　greater　at　acidic　and　high　PI　concentrations,　but　significantly　decreased　in　the　presence　of　natural　organic　matter.　The　presence　of　anions　in　the　water　did　not　obviously　impact　NEO　degradation.　During　the　degradation　of　NEO,　•OH　attacked　NEO　through　hydroxylation　reaction,　while　IO3•　and　1O2　predominantly　participated　in　decarboxylation　and　amide　hydrolysis　reactions.　Toxicity　evaluation　showed　that　the　UV/PI　treatment　of　NEO　enhanced　the　toxicity　to　Vibrio　fischeri　within　5　min,　and　the　toxicity　reduced　with　the　prolongation　of　treatment　time.　The　study　provides　meaningful　information　on　the　roles　of　IO3•　and　1O2　for　NEO　degradation　by　UV/PI.　©　2024　Elsevier　B.V.