To　investigate　the　relationship　between　worry　tendency　and　sleep　quality　and　the　mediating　effect　of　state-trait　anxiety,　1072　adolescents　and　young　adults　from　Jiangxi　and　Fujian　Provinces　in　China　were　administered　questionnaires　pertaining　to　worry　tendency,　sleep　quality,　and　state-trait　anxiety.　The　results　showed　significant　grade　differences　for　worry　tendency,　sleep　quality,　and　state-trait　anxiety.　Worry　tendency　was　negatively　associated　with　sleep　quality,　which　was　mediated　by　state　anxiety　and　trait　anxiety.　There　is　a　need　for　interventions　that　aim　to　reduce　the　level　of　worry　tendency　to　ensure　good　sleep　quality　and　the　progression　from　worry　tendency　to　anxiety　and　to　poor　sleep　quality.　©　2013　The　Author(s).