the domain constraint (in class Buch): type(inList:["Roman","Märchen"]) expands via "grails generate-views" to <g:select name='type' from='${buch.constraints.type.inList.collect{it.encodeAsHTML()}}' value="${buch.type?.encodeAsHTML()}"></g:select> which is being rendered as: ... <option value="Roman" >Roman</option> <option value="Märchen" >M&auml;rchen</option> The "amp;" is not correct here. Just leaving out the encodeHTML() however creates <option value="Märchen" >Märchen</option> which is correct as value is now unescaped.