diff --git a/src/changes/changes.xml b/src/changes/changes.xml
index 6828fb1c0..59c6d67ba 100644
--- a/src/changes/changes.xml
+++ b/src/changes/changes.xml
@@ -64,6 +64,7 @@ The <action> type attribute can be add,update,fix,remove.
   <body>
   <release version="1.11.1" date="YYYY-MM-DD" description="This is a feature and maintenance release. Java 8 or later is required.">
     <!-- FIX -->
+    <action type="fix" issue="VALIDATOR-510" due-to="Aryan Ganjoo">IBANValidator.setValidator() preserves unrelated secondary country codes when changing an alias.</action>
     <action type="fix" dev="ggregory" due-to="sahvx655-wq, Gary Gregory">Drop the symbol separator in the currency and percent re-parse (#430).</action>
     <action type="fix" dev="ggregory" due-to="sahvx655-wq, Gary Gregory">Count unpaired carriage returns in adjustForLineEnding (#431).</action>
     <action type="fix" dev="ggregory" due-to="sahvx655-wq, Gary Gregory">Validate path, query and fragment for authority-less file URLs (#432).</action>
diff --git a/src/main/java/org/apache/commons/validator/routines/IBANValidator.java b/src/main/java/org/apache/commons/validator/routines/IBANValidator.java
index 3052fb09f..9bd8762f4 100644
--- a/src/main/java/org/apache/commons/validator/routines/IBANValidator.java
+++ b/src/main/java/org/apache/commons/validator/routines/IBANValidator.java
@@ -360,6 +360,25 @@ public boolean isValid(final String code) {
         return validate(code) == IBANValidatorStatus.VALID;
     }
 
+    /**
+     * Removes the other country codes of a validator that was replaced or removed under the given country code.
+     * <p>
+     * Nothing is removed when the country code was one of the other country codes of the previous validator (for example
+     * AX for FI), since the previous validator remains installed under its own country code. Only entries that still map to
+     * the previous validator are removed, so other country codes that have since been given their own validator are kept.
+     * </p>
+     *
+     * @param countryCode The country code that was replaced or removed.
+     * @param prev        The validator previously installed for the country code, may be null.
+     */
+    private void removeOtherCountryCodes(final String countryCode, final Validator prev) {
+        if (prev != null && prev.countryCode.equals(countryCode)) {
+            for (final String otherCC : prev.otherCountryCodes) {
+                validatorMap.remove(otherCC, prev);
+            }
+        }
+    }
+
     /**
      * Installs a validator. Will replace any existing entry which has the same countryCode.
      *
@@ -376,11 +395,7 @@ public Validator setValidator(final String countryCode, final int length, final
         }
         if (length < 0) {
             final Validator prev = validatorMap.remove(countryCode);
-            if (prev != null) {
-                for (final String otherCC : prev.otherCountryCodes) {
-                    validatorMap.remove(otherCC);
-                }
-            }
+            removeOtherCountryCodes(countryCode, prev);
             return prev;
         }
         return setValidator(new Validator(countryCode, length, format));
@@ -398,11 +413,7 @@ public Validator setValidator(final Validator validator) {
             throw new IllegalStateException("The singleton validator cannot be modified");
         }
         final Validator prev = validatorMap.put(validator.countryCode, validator);
-        if (prev != null) {
-            for (final String otherCC : prev.otherCountryCodes) {
-                validatorMap.remove(otherCC);
-            }
-        }
+        removeOtherCountryCodes(validator.countryCode, prev);
         for (final String otherCC : validator.otherCountryCodes) {
             validatorMap.put(otherCC, validator);
         }
diff --git a/src/test/java/org/apache/commons/validator/routines/IBANValidatorTest.java b/src/test/java/org/apache/commons/validator/routines/IBANValidatorTest.java
index 95c908984..7ca2ff42a 100644
--- a/src/test/java/org/apache/commons/validator/routines/IBANValidatorTest.java
+++ b/src/test/java/org/apache/commons/validator/routines/IBANValidatorTest.java
@@ -513,6 +513,37 @@ void testSetValidatorReplaceOtherCountryCodes() {
         assertFalse(validator.hasValidator("IM"));
     }
 
+    @Test
+    void testSetValidatorForOtherCountryCode() {
+        final IBANValidator validator = new IBANValidator();
+        // AX (Aland Islands) is handled by the FI (Finland) validator by default
+        assertEquals(validator.getValidator("FI"), validator.getValidator("AX"));
+        // Give AX its own validator
+        final Validator axValidator = new Validator("AX", 18, "AX\\d{16}");
+        assertEquals(validator.getValidator("FI"), validator.setValidator(axValidator));
+        assertEquals(axValidator, validator.getValidator("AX"));
+        assertTrue(validator.isValid("AX2112345600000785"));
+        assertTrue(validator.isValid("FI2112345600000785"));
+        // Replacing FI must not remove the AX validator, which no longer belongs to FI
+        validator.setValidator(new Validator("FI", 18, "FI\\d{16}"));
+        assertEquals(axValidator, validator.getValidator("AX"));
+    }
+
+    @Test
+    void testSetValidatorRemoveOtherCountryCode() {
+        final IBANValidator validator = new IBANValidator();
+        // GF (French Guiana) and GP (Guadeloupe) are handled by the FR (France) validator by default
+        final Validator frValidator = validator.getValidator("FR");
+        assertEquals(frValidator, validator.getValidator("GF"));
+        assertEquals(frValidator, validator.getValidator("GP"));
+        // Removing GF must only remove GF
+        assertEquals(frValidator, validator.setValidator("GF", -1, null));
+        assertFalse(validator.hasValidator("GF"));
+        assertEquals(frValidator, validator.getValidator("FR"));
+        assertEquals(frValidator, validator.getValidator("GP"));
+        assertTrue(validator.isValid("GP1120041010050500013M02606"));
+    }
+
     @Test
     void testSorted() {
         final IBANValidator validator = new IBANValidator();