Herbicidal 5-acylamino-pyrazole derivatives of the formula ##STR1## in which R.sup.1 represents hydrogen, halogen or nitro,R.sup.2 represents hydrogen, alkyl, alkenyl, alkinyl or optionally substituted cycloalkyl,R.sup.3 represents hydrogen or alkyl, or represents optionally substituted cycloalkyl, or represents optionally substituted aryl,Ar represents in each case optionally substituted phenyl or pyridyl,X.sup.1 represents oxygen or sulphur,A represents a straight-chain or branched optionally substituted alkylene bridge,n represents the number 0 to 1 andX.sup.2 represents oxygen, or represents a radical .dbd.N--O--R.sup.4, or represents a radical ##STR2## wherein R.sup.4 represents hydrogen, alkyl, alkenyl, alkinyl, halogenoalkyl, halogenoalkenyl, alkoxyalkyl or alkylthioalkyl, or represents optionally substituted aralkyl, or represents optionally substituted aryl,R.sup.5 represents hydrogen or alkyl andR.sup.6 represents hydrogen or alkyl, or represents optionally substituted aryl, or represents a radical ##STR3## wherein X.sup.3 represents oxygen or sulphur andR.sup.7 represents hydrogen, alkyl, alkoxy, alkylamino or dialkylamino.