diff --git a/docs/what/urn.md b/docs/what/urn.md
index 2f4dffb985653..c7fb0555cd992 100644
--- a/docs/what/urn.md
+++ b/docs/what/urn.md
@@ -35,11 +35,17 @@ urn:li:dataset:(urn:li:dataPlatform:hdfs,PageViewEvent,EI)
 
 ## Restrictions
 
-There are a few restrictions when creating an urn:
+There are a few restrictions when creating an URN:
 
-1. Commas are reserved character in URN fields: `,`
-2. Parentheses are reserved characters in URN fields: `(` or `)`
-3. Colons are reserved characters in URN fields: `:`
-4. Urn separator UTF-8 character `␟`
+The following characters are not allowed anywhere in the URN
+
+1. Parentheses are reserved characters in URN fields: `(` or `)`
+2. The "unit separator" unicode character `␟` (U+241F)
+
+The following characters are not allowed within an URN tuple.
+
+1. Commas are reserved characters in URN tuples: `,`
+
+Example: `urn:li:dashboard:(looker,dashboards.thelook)` is a valid urn, but `urn:li:dashboard:(looker,dashboards.the,look)` is invalid.
 
 Please do not use these characters when creating or generating urns. One approach is to use URL encoding for the characters.
diff --git a/metadata-io/metadata-io-api/build.gradle b/metadata-io/metadata-io-api/build.gradle
index b8028fad07bb6..5273177b75281 100644
--- a/metadata-io/metadata-io-api/build.gradle
+++ b/metadata-io/metadata-io-api/build.gradle
@@ -16,3 +16,7 @@ dependencies {
   testImplementation externalDependency.lombok
   testAnnotationProcessor externalDependency.lombok
 }
+
+test {
+  environment 'STRICT_URN_VALIDATION_ENABLED', 'true'
+}
\ No newline at end of file
diff --git a/metadata-io/metadata-io-api/src/main/java/com/linkedin/metadata/entity/validation/ValidationApiUtils.java b/metadata-io/metadata-io-api/src/main/java/com/linkedin/metadata/entity/validation/ValidationApiUtils.java
index c2e1c47eca1fd..5e1f09fcc6439 100644
--- a/metadata-io/metadata-io-api/src/main/java/com/linkedin/metadata/entity/validation/ValidationApiUtils.java
+++ b/metadata-io/metadata-io-api/src/main/java/com/linkedin/metadata/entity/validation/ValidationApiUtils.java
@@ -30,7 +30,8 @@ public class ValidationApiUtils {
   // Related to BrowsePathv2
   public static final String URN_DELIMITER_SEPARATOR = "␟";
   // https://datahubproject.io/docs/what/urn/#restrictions
-  public static final Set<String> ILLEGAL_URN_COMPONENT_CHARACTERS = Set.of(":", "(", ")", ",");
+  public static final Set<String> ILLEGAL_URN_COMPONENT_CHARACTERS = Set.of("(", ")");
+  public static final Set<String> ILLEGAL_URN_TUPLE_CHARACTERS = Set.of(",");
 
   /**
    * Validates a {@link RecordTemplate} and throws {@link ValidationException} if validation fails.
@@ -86,11 +87,10 @@ public static void validateUrn(
           "Error: URN cannot contain " + URN_DELIMITER_SEPARATOR + " character");
     }
 
+    int totalParts = urn.getEntityKey().getParts().size();
     List<String> illegalComponents =
         urn.getEntityKey().getParts().stream()
-            .flatMap(ValidationApiUtils::processUrnPartRecursively)
-            .filter(
-                urnPart -> ILLEGAL_URN_COMPONENT_CHARACTERS.stream().anyMatch(urnPart::contains))
+            .flatMap(part -> processUrnPartRecursively(part, totalParts))
             .collect(Collectors.toList());
 
     if (!illegalComponents.isEmpty()) {
@@ -114,15 +114,25 @@ public static void validateUrn(
   }
 
   /** Recursively process URN parts with URL decoding */
-  private static Stream<String> processUrnPartRecursively(String urnPart) {
+  private static Stream<String> processUrnPartRecursively(String urnPart, int totalParts) {
     String decodedPart =
         URLDecoder.decode(URLEncodingFixer.fixURLEncoding(urnPart), StandardCharsets.UTF_8);
     if (decodedPart.startsWith("urn:li:")) {
       // Recursively process nested URN after decoding
+      int nestedParts = UrnUtils.getUrn(decodedPart).getEntityKey().getParts().size();
       return UrnUtils.getUrn(decodedPart).getEntityKey().getParts().stream()
-          .flatMap(ValidationApiUtils::processUrnPartRecursively);
+          .flatMap(part -> processUrnPartRecursively(part, nestedParts));
     }
-    return Stream.of(decodedPart);
+    if (totalParts > 1) {
+      if (ILLEGAL_URN_TUPLE_CHARACTERS.stream().anyMatch(c -> urnPart.contains(c))) {
+        return Stream.of(urnPart);
+      }
+    }
+    if (ILLEGAL_URN_COMPONENT_CHARACTERS.stream().anyMatch(c -> urnPart.contains(c))) {
+      return Stream.of(urnPart);
+    }
+
+    return Stream.empty();
   }
 
   /**
diff --git a/metadata-io/metadata-io-api/src/test/java/com/linkedin/metadata/entity/validation/ValidationApiUtilsTest.java b/metadata-io/metadata-io-api/src/test/java/com/linkedin/metadata/entity/validation/ValidationApiUtilsTest.java
index e683e594d8766..a2c9a15d92f90 100644
--- a/metadata-io/metadata-io-api/src/test/java/com/linkedin/metadata/entity/validation/ValidationApiUtilsTest.java
+++ b/metadata-io/metadata-io-api/src/test/java/com/linkedin/metadata/entity/validation/ValidationApiUtilsTest.java
@@ -18,10 +18,36 @@ public void testValidateDatasetUrn() {
     // If no exception is thrown, test passes
   }
 
-  @Test(expectedExceptions = IllegalArgumentException.class)
+  @Test
   public void testSimpleUrnColon() {
-    Urn invalidUrn = UrnUtils.getUrn("urn:li:corpuser:foo:bar");
-    ValidationApiUtils.validateUrn(entityRegistry, invalidUrn, true);
+    ValidationApiUtils.validateUrn(
+        entityRegistry, UrnUtils.getUrn("urn:li:corpuser:foo:bar"), true);
+    ValidationApiUtils.validateUrn(
+        entityRegistry, UrnUtils.getUrn("urn:li:dataPlatform:abc:def"), true);
+    ValidationApiUtils.validateUrn(
+        entityRegistry, UrnUtils.getUrn("urn:li:corpuser:foo:bar@example.com"), true);
+    // If no exception is thrown, test passes
+  }
+
+  @Test
+  public void testSimpleUrnComma() {
+    ValidationApiUtils.validateUrn(entityRegistry, UrnUtils.getUrn("urn:li:corpuser:,"), true);
+    // If no exception is thrown, test passes
+  }
+
+  @Test(expectedExceptions = IllegalArgumentException.class)
+  public void testTupleUrnComma() {
+    ValidationApiUtils.validateUrn(
+        entityRegistry, UrnUtils.getUrn("urn:li:dashboard:(looker,dashboards,thelook)"), true);
+  }
+
+  @Test(expectedExceptions = IllegalArgumentException.class)
+  public void testFabricTypeCasing() {
+    // prod != PROD
+    ValidationApiUtils.validateUrn(
+        entityRegistry,
+        UrnUtils.getUrn("urn:li:dataset:(urn:li:dataPlatform:abc:def,table_name,prod)"),
+        true);
   }
 
   @Test
@@ -34,7 +60,7 @@ public void testComplexUrnColon() throws URISyntaxException {
   }
 
   @Test(expectedExceptions = IllegalArgumentException.class)
-  public void testUrnFabricType() {
+  public void testFabricTypeParen() {
     Urn invalidUrn = UrnUtils.getUrn("urn:li:dataset:(urn:li:dataPlatform:hdfs,/path/to/data,())");
     ValidationApiUtils.validateUrn(entityRegistry, invalidUrn, true);
   }
@@ -83,20 +109,20 @@ public void testValidComplexUrn() {
         UrnUtils.getUrn(
             "urn:li:dataset:(urn:li:dataPlatform:bigquery,myproject.dataset.table,PROD)");
 
-    ValidationApiUtils.validateUrn(entityRegistry, validUrn);
+    ValidationApiUtils.validateUrn(entityRegistry, validUrn, true);
     // If no exception is thrown, test passes
   }
 
   @Test(expectedExceptions = NullPointerException.class)
   public void testUrnNull() {
-    ValidationApiUtils.validateUrn(entityRegistry, null);
+    ValidationApiUtils.validateUrn(entityRegistry, null, true);
   }
 
   @Test
   public void testValidPartialUrlEncode() {
     Urn validUrn = UrnUtils.getUrn("urn:li:assertion:123=-%28__% weekly__%29");
 
-    ValidationApiUtils.validateUrn(entityRegistry, validUrn);
+    ValidationApiUtils.validateUrn(entityRegistry, validUrn, true);
     // If no exception is thrown, test passes
   }
 
@@ -106,7 +132,23 @@ public void testValidPartialUrlEncode2() {
         UrnUtils.getUrn(
             "urn:li:dataset:(urn:li:dataPlatform:s3,urn:li:dataset:%28urn:li:dataPlatform:s3%2Ctest-datalake-concepts%prog_maintenance%2CPROD%29,PROD)");
 
-    ValidationApiUtils.validateUrn(entityRegistry, validUrn);
+    ValidationApiUtils.validateUrn(entityRegistry, validUrn, true);
+    // If no exception is thrown, test passes
+  }
+
+  @Test
+  public void testValidColon() {
+    Urn validUrn =
+        UrnUtils.getUrn("urn:li:dashboard:(looker,dashboards.thelook::cohort_data_tool)");
+
+    ValidationApiUtils.validateUrn(entityRegistry, validUrn, true);
+    // If no exception is thrown, test passes
+  }
+
+  @Test
+  public void testNoTupleComma() {
+    Urn invalidUrn = UrnUtils.getUrn("urn:li:corpuser:,");
+    ValidationApiUtils.validateUrn(entityRegistry, invalidUrn, true);
     // If no exception is thrown, test passes
   }
 }