diff --git a/src/main/java/org/apache/xmlbeans/impl/values/JavaStringHolderEx.java b/src/main/java/org/apache/xmlbeans/impl/values/JavaStringHolderEx.java
index 1a7fd8df8..4e581c94e 100644
--- a/src/main/java/org/apache/xmlbeans/impl/values/JavaStringHolderEx.java
+++ b/src/main/java/org/apache/xmlbeans/impl/values/JavaStringHolderEx.java
@@ -62,13 +62,17 @@ public static void validateLexical(String v, SchemaType sType, ValidationContext
             return;
         }
 
+        // xsd length facets count characters (code points), not Java UTF-16
+        // code units, so a supplementary character counts as one
+        int cch = v.codePointCount(0, v.length());
+
         // check against length
         XmlObject len = sType.getFacet(SchemaType.FACET_LENGTH);
         if (len != null) {
             int m = ((XmlObjectBase) len).getBigIntegerValue().intValue();
-            if (v.length() != m) {
+            if (cch != m) {
                 context.invalid(XmlErrorCodes.DATATYPE_LENGTH_VALID$STRING,
-                    new Object[]{"string", v.length(), m, QNameHelper.readable(sType)});
+                    new Object[]{"string", cch, m, QNameHelper.readable(sType)});
                 return;
             }
         }
@@ -77,9 +81,9 @@ public static void validateLexical(String v, SchemaType sType, ValidationContext
         XmlObject min = sType.getFacet(SchemaType.FACET_MIN_LENGTH);
         if (min != null) {
             int m = ((XmlObjectBase) min).getBigIntegerValue().intValue();
-            if (v.length() < m) {
+            if (cch < m) {
                 context.invalid(XmlErrorCodes.DATATYPE_MIN_LENGTH_VALID$STRING,
-                    new Object[]{"string", v.length(), m, QNameHelper.readable(sType)});
+                    new Object[]{"string", cch, m, QNameHelper.readable(sType)});
                 return;
             }
         }
@@ -88,9 +92,9 @@ public static void validateLexical(String v, SchemaType sType, ValidationContext
         XmlObject max = sType.getFacet(SchemaType.FACET_MAX_LENGTH);
         if (max != null) {
             int m = ((XmlObjectBase) max).getBigIntegerValue().intValue();
-            if (v.length() > m) {
+            if (cch > m) {
                 context.invalid(XmlErrorCodes.DATATYPE_MAX_LENGTH_VALID$STRING,
-                    new Object[]{"string", v.length(), m, QNameHelper.readable(sType)});
+                    new Object[]{"string", cch, m, QNameHelper.readable(sType)});
                 return;
             }
         }
diff --git a/src/main/java/org/apache/xmlbeans/impl/values/JavaUriHolderEx.java b/src/main/java/org/apache/xmlbeans/impl/values/JavaUriHolderEx.java
index 41817bc3d..1d8f5a4f4 100644
--- a/src/main/java/org/apache/xmlbeans/impl/values/JavaUriHolderEx.java
+++ b/src/main/java/org/apache/xmlbeans/impl/values/JavaUriHolderEx.java
@@ -95,22 +95,26 @@ public static void validateLexical(String v, SchemaType sType, ValidationContext
         XmlObject x;
         int i;
 
+        // xsd length facets count characters (code points), not Java UTF-16
+        // code units, so a supplementary character counts as one
+        int cch = v.codePointCount(0, v.length());
+
         if ((x = sType.getFacet(SchemaType.FACET_LENGTH)) != null) {
-            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) != v.length()) {
+            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) != cch) {
                 context.invalid(XmlErrorCodes.DATATYPE_LENGTH_VALID$STRING,
                     new Object[]{"anyURI", v, i, QNameHelper.readable(sType)});
             }
         }
 
         if ((x = sType.getFacet(SchemaType.FACET_MIN_LENGTH)) != null) {
-            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) > v.length()) {
+            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) > cch) {
                 context.invalid(XmlErrorCodes.DATATYPE_MIN_LENGTH_VALID$STRING,
                     new Object[]{"anyURI", v, i, QNameHelper.readable(sType)});
             }
         }
 
         if ((x = sType.getFacet(SchemaType.FACET_MAX_LENGTH)) != null) {
-            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) < v.length()) {
+            if ((i = ((SimpleValue) x).getBigIntegerValue().intValue()) < cch) {
                 context.invalid(XmlErrorCodes.DATATYPE_MAX_LENGTH_VALID$STRING,
                     new Object[]{"anyURI", v, i, QNameHelper.readable(sType)});
             }
diff --git a/src/test/java/misc/checkin/StringLengthFacetCodePointTest.java b/src/test/java/misc/checkin/StringLengthFacetCodePointTest.java
new file mode 100644
index 000000000..ebbe4deba
--- /dev/null
+++ b/src/test/java/misc/checkin/StringLengthFacetCodePointTest.java
@@ -0,0 +1,62 @@
+/*   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements.  See the NOTICE file distributed with
+ *   this work for additional information regarding copyright ownership.
+ *   The ASF licenses this file to You under the Apache License, Version 2.0
+ *   (the "License"); you may not use this file except in compliance with
+ *   the License.  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *   Unless required by applicable law or agreed to in writing, software
+ *   distributed under the License is distributed on an "AS IS" BASIS,
+ *   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *   See the License for the specific language governing permissions and
+ *   limitations under the License.
+ */
+
+package misc.checkin;
+
+import org.apache.xmlbeans.SchemaTypeLoader;
+import org.apache.xmlbeans.XmlBeans;
+import org.apache.xmlbeans.XmlObject;
+import org.apache.xmlbeans.impl.xb.xsdschema.SchemaDocument;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class StringLengthFacetCodePointTest {
+
+    // U+1D54F MATHEMATICAL DOUBLE-STRUCK CAPITAL X: one character, encoded as a
+    // surrogate pair so String.length() is 2 but codePointCount is 1
+    private static final String SUPPLEMENTARY = "𝕏";
+
+    private static boolean validates(String base, String facet, String value) throws Exception {
+        String xsd =
+            "<xs:schema xmlns:xs='http://www.w3.org/2001/XMLSchema' xmlns:t='urn:t' " +
+            "targetNamespace='urn:t' elementFormDefault='qualified'>" +
+            "  <xs:element name='root'>" +
+            "    <xs:simpleType><xs:restriction base='" + base + "'>" + facet +
+            "</xs:restriction></xs:simpleType>" +
+            "  </xs:element>" +
+            "</xs:schema>";
+        SchemaTypeLoader loader = XmlBeans.loadXsd(new XmlObject[]{SchemaDocument.Factory.parse(xsd)});
+        XmlObject doc = loader.parse("<t:root xmlns:t='urn:t'>" + value + "</t:root>", null, null);
+        return doc.validate();
+    }
+
+    @Test
+    void stringLengthFacetsCountCharactersNotCodeUnits() throws Exception {
+        // one supplementary character is one xsd character, so it meets length/maxLength of 1
+        assertTrue(validates("xs:string", "<xs:length value='1'/>", SUPPLEMENTARY));
+        assertTrue(validates("xs:string", "<xs:maxLength value='1'/>", SUPPLEMENTARY));
+        // it is one character, so it does not meet a length of 2
+        assertFalse(validates("xs:string", "<xs:length value='2'/>", SUPPLEMENTARY));
+    }
+
+    @Test
+    void anyUriLengthFacetsCountCharactersNotCodeUnits() throws Exception {
+        assertTrue(validates("xs:anyURI", "<xs:length value='1'/>", SUPPLEMENTARY));
+        assertTrue(validates("xs:anyURI", "<xs:maxLength value='1'/>", SUPPLEMENTARY));
+    }
+}