Sustainable　and　green　energy　sources　are　in　high　demand　to　meet　the　current　human　energy　needs　and　environmental　requirements.　Hydrogen　energy,　with　the　highest　energy　density　and　zero　carbon　emission,　is　considered　a　potential　solution.　Hydrogen　is　primarily　produced　by　splitting　water.　Rationally　designed　electrocatalysts　are　required　to　promote　the　cathodic　hydrogen　evolution　reaction　(HER)　and　the　anodic　oxygen　evolution　reaction　(OER).　Organic　polymer　matrices　provide　new　opportunities　for　electrocatalytic　water　splitting　due　to　their　special　physical　and　chemical　characteristics　and　thermal　stability.　This　article　explains　the　role　of　organic　polymers　in　electrocatalytic　water　decomposition　from　three　aspects:　ion-conductive　polymers,　conjugated　conductive　polymers,　and　carbon　materials　derived　from　organic　polymers.　We　hope　that　this　article　will　provide　more　rational　ideas　and　promote　the　design　of　organic　polymers　for　water-splitting　electrocatalysis,　and　furnish　more　technical　insights　for　the　future　of　water　electrolysis.