diff --git a/hibernate-core/src/main/java/org/hibernate/cfg/Configuration.java b/hibernate-core/src/main/java/org/hibernate/cfg/Configuration.java
index 5a3a66d274..e31728cec8 100644
--- a/hibernate-core/src/main/java/org/hibernate/cfg/Configuration.java
+++ b/hibernate-core/src/main/java/org/hibernate/cfg/Configuration.java
@@ -2418,7 +2418,9 @@ public class Configuration implements Serializable {
 	}
 
 	public void addSqlFunction(String functionName, SQLFunction function) {
-		sqlFunctions.put( functionName, function );
+		// HHH-7721: SQLFunctionRegistry expects all lowercase.  Enforce,
+		// just in case a user's customer dialect uses mixed cases.
+		sqlFunctions.put( functionName.toLowerCase(), function );
 	}
 
 	public TypeResolver getTypeResolver() {
diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java b/hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java
index bc7835d061..87793bcce1 100644
--- a/hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java
+++ b/hibernate-core/src/main/java/org/hibernate/dialect/Dialect.java
@@ -598,7 +598,9 @@ public abstract class Dialect implements ConversionContext {
 	// function support ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 	protected void registerFunction(String name, SQLFunction function) {
-		sqlFunctions.put( name, function );
+		// HHH-7721: SQLFunctionRegistry expects all lowercase.  Enforce,
+		// just in case a user's customer dialect uses mixed cases.
+		sqlFunctions.put( name.toLowerCase(), function );
 	}
 
 	/**
diff --git a/hibernate-core/src/main/java/org/hibernate/dialect/function/SQLFunctionRegistry.java b/hibernate-core/src/main/java/org/hibernate/dialect/function/SQLFunctionRegistry.java
index e013421538..9eec303f82 100644
--- a/hibernate-core/src/main/java/org/hibernate/dialect/function/SQLFunctionRegistry.java
+++ b/hibernate-core/src/main/java/org/hibernate/dialect/function/SQLFunctionRegistry.java
@@ -38,7 +38,6 @@ public class SQLFunctionRegistry {
 	}
 	
 	public SQLFunction findSQLFunction(String functionName) {
-		// TODO: lower casing done here. Was done "at random" before; maybe not needed at all ?
 		String name = functionName.toLowerCase();
 		SQLFunction userFunction = userFunctions.get( name );
 		return userFunction != null
@@ -47,7 +46,6 @@ public class SQLFunctionRegistry {
 	}
 
 	public boolean hasFunction(String functionName) {
-		// TODO: toLowerCase was not done before. Only used in Template.
 		String name = functionName.toLowerCase();
 		return userFunctions.containsKey( name ) || dialect.getFunctions().containsKey( name );
 	}
diff --git a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/SessionFactoryHelper.java b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/SessionFactoryHelper.java
index 6b56e102bb..22c57349b4 100644
--- a/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/SessionFactoryHelper.java
+++ b/hibernate-core/src/main/java/org/hibernate/hql/internal/ast/util/SessionFactoryHelper.java
@@ -361,7 +361,7 @@ public class SessionFactoryHelper {
 	 * @return The sql function, or null if not found.
 	 */
 	public SQLFunction findSQLFunction(String functionName) {
-		return sfi.getSqlFunctionRegistry().findSQLFunction( functionName.toLowerCase() );
+		return sfi.getSqlFunctionRegistry().findSQLFunction( functionName );
 	}
 
 	/**