diff --git a/java-spiffe-core/src/main/java/io/spiffe/spiffeid/SpiffeId.java b/java-spiffe-core/src/main/java/io/spiffe/spiffeid/SpiffeId.java
index 0f6c8499..b04257c1 100644
--- a/java-spiffe-core/src/main/java/io/spiffe/spiffeid/SpiffeId.java
+++ b/java-spiffe-core/src/main/java/io/spiffe/spiffeid/SpiffeId.java
@@ -72,18 +72,25 @@ public static SpiffeId parse(final String id) {
             throw new IllegalArgumentException(EMPTY);
         }
 
-        if (!id.startsWith(SCHEME_PREFIX)) {
+        int schemeSeparatorIndex = id.indexOf("://");
+        if (schemeSeparatorIndex <= 0) {
             throw new InvalidSpiffeIdException(WRONG_SCHEME);
         }
 
-        String rest = id.substring(SCHEME_PREFIX.length());
+        String scheme = id.substring(0, schemeSeparatorIndex);
+        if (!SPIFFE_SCHEME.equalsIgnoreCase(scheme)) {
+            throw new InvalidSpiffeIdException(WRONG_SCHEME);
+        }
+
+        String rest = id.substring(schemeSeparatorIndex + 3);
 
         int i = 0;
         for (char c : rest.toCharArray()) {
             if (c == '/') {
                 break;
             }
-            if (!isValidTrustDomainChar(c)) {
+            char normalized = Character.toLowerCase(c);
+            if (!isValidTrustDomainChar(normalized)) {
                 throw new InvalidSpiffeIdException(BAD_TRUST_DOMAIN_CHAR);
             }
             i++;
@@ -100,7 +107,8 @@ public static SpiffeId parse(final String id) {
             validatePath(path);
         }
 
-        return new SpiffeId(new TrustDomain(td), path);
+        String normalizedTrustDomain = td.toLowerCase();
+        return new SpiffeId(new TrustDomain(normalizedTrustDomain), path);
     }
 
     /**
diff --git a/java-spiffe-core/src/main/java/io/spiffe/spiffeid/TrustDomain.java b/java-spiffe-core/src/main/java/io/spiffe/spiffeid/TrustDomain.java
index 7a26ff26..0eca961e 100644
--- a/java-spiffe-core/src/main/java/io/spiffe/spiffeid/TrustDomain.java
+++ b/java-spiffe-core/src/main/java/io/spiffe/spiffeid/TrustDomain.java
@@ -41,8 +41,9 @@ public static TrustDomain parse(String idOrName) {
             return SpiffeId.parse(idOrName).getTrustDomain();
         }
 
-        validateTrustDomainName(idOrName);
-        return new TrustDomain(idOrName);
+        String normalizedName = idOrName.toLowerCase();
+        validateTrustDomainName(normalizedName);
+        return new TrustDomain(normalizedName);
     }
 
     /**
diff --git a/java-spiffe-core/src/test/java/io/spiffe/spiffeid/SpiffeIdTest.java b/java-spiffe-core/src/test/java/io/spiffe/spiffeid/SpiffeIdTest.java
index fd6829f6..6ab69519 100644
--- a/java-spiffe-core/src/test/java/io/spiffe/spiffeid/SpiffeIdTest.java
+++ b/java-spiffe-core/src/test/java/io/spiffe/spiffeid/SpiffeIdTest.java
@@ -64,7 +64,9 @@ static Stream<Arguments> provideTestValidSpiffeIds() {
                 Arguments.of("spiffe://trustdomain/path", TrustDomain.parse("trustdomain"), "/path"),
                 Arguments.of("spiffe://trustdomain/path1/path2", TrustDomain.parse("trustdomain"), "/path1/path2"),
                 Arguments.of("spiffe://trustdomain/PATH1/PATH2", TrustDomain.parse("trustdomain"), "/PATH1/PATH2"),
-                Arguments.of("spiffe://trustdomain/9eebccd2-12bf-40a6-b262-65fe0487d453", TrustDomain.parse("trustdomain"), "/9eebccd2-12bf-40a6-b262-65fe0487d453")
+                Arguments.of("spiffe://trustdomain/9eebccd2-12bf-40a6-b262-65fe0487d453", TrustDomain.parse("trustdomain"), "/9eebccd2-12bf-40a6-b262-65fe0487d453"),
+                Arguments.of("SPIFFE://trustdomain/path", TrustDomain.parse("trustdomain"), "/path"),
+                Arguments.of("SpIfFe://TrUsTdOmAiN/Workload", TrustDomain.parse("trustdomain"), "/Workload")
         );
     }
 
@@ -92,7 +94,7 @@ static Stream<Arguments> provideInvalidSpiffeIds() {
                 Arguments.of("spiffe://user:password@test.org/path/element", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
                 Arguments.of("spiffe:path/element", "Scheme is missing or invalid"),
                 Arguments.of("spiffe:/path/element", "Scheme is missing or invalid"),
-                Arguments.of("SPIFFE://path/element", "Scheme is missing or invalid"),
+                Arguments.of("spiffe://", "Trust domain is missing"),
                 Arguments.of("spiffe://domain.test/path/elem%5uent", "Path segment characters are limited to letters, numbers, dots, dashes, and underscores"),
                 Arguments.of("spiffe://trustdomain/path//", "Path cannot contain empty segments"),
                 Arguments.of("spiffe://trustdomain/./other", "Path cannot contain dot segments"),
@@ -173,9 +175,10 @@ void testParseWithAllChars() {
 
             String td = "spiffe://trustdomain" + c;
 
-            if (TD_CHARS.contains(c)) {
+            char normalizedTdChar = Character.toLowerCase(c);
+            if (TrustDomain.isValidTrustDomainChar(normalizedTdChar)) {
                 SpiffeId spiffeId = SpiffeId.parse(td);
-                assertEquals(spiffeId.toString(), td);
+                assertEquals("spiffe://trustdomain" + normalizedTdChar, spiffeId.toString());
             } else {
                 try {
                     SpiffeId.parse(td);
diff --git a/java-spiffe-core/src/test/java/io/spiffe/spiffeid/TrustDomainTest.java b/java-spiffe-core/src/test/java/io/spiffe/spiffeid/TrustDomainTest.java
index 5dc9bde8..8e4cc8b9 100644
--- a/java-spiffe-core/src/test/java/io/spiffe/spiffeid/TrustDomainTest.java
+++ b/java-spiffe-core/src/test/java/io/spiffe/spiffeid/TrustDomainTest.java
@@ -7,8 +7,6 @@
 import org.junit.jupiter.params.provider.MethodSource;
 
 import java.util.stream.Stream;
-
-import static io.spiffe.spiffeid.SpiffeIdTest.TD_CHARS;
 import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.fail;
@@ -22,6 +20,12 @@ void testTrustDomainFromName() {
         assertEquals("trustdomain", trustDomain.getName());
     }
 
+    @Test
+    void testTrustDomainFromNameMixedCase_isNormalizedToLowercase() {
+        TrustDomain trustDomain = TrustDomain.parse("TrUsTdOmAiN");
+        assertEquals("trustdomain", trustDomain.getName());
+    }
+
     @Test
     void testFromIdStringWithoutPath() {
         TrustDomain trustDomain = TrustDomain.parse("spiffe://trustdomain");
@@ -41,9 +45,10 @@ void testAllChars() {
             char c = (char) i;
             String td = "trustdomain" + c;
 
-            if (TD_CHARS.contains(c)) {
+            char normalizedTdChar = Character.toLowerCase(c);
+            if (TrustDomain.isValidTrustDomainChar(normalizedTdChar)) {
                 TrustDomain trustDomain = TrustDomain.parse(td);
-                assertEquals(td, trustDomain.getName());
+                assertEquals("trustdomain" + normalizedTdChar, trustDomain.getName());
             } else {
                 try {
                     TrustDomain.parse(td);
@@ -70,8 +75,8 @@ static Stream<Arguments> provideInvalidTrustDomain() {
                 Arguments.of("", "Trust domain is missing"),
                 Arguments.of("spiffe://", "Trust domain is missing"),
                 Arguments.of(null, "idOrName must not be null"),
-                Arguments.of("Trustdomain", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
-                Arguments.of("spiffe://Domain.test", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
+                Arguments.of("trustdomain!", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
+                Arguments.of("spiffe://domain!.test", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
                 Arguments.of("spiffe://domain.test/spiffe://domain.test/path/element", "Path segment characters are limited to letters, numbers, dots, dashes, and underscores"),
                 Arguments.of("http://domain.test", "Scheme is missing or invalid"),
                 Arguments.of("spiffe:// domain.test ", "Trust domain characters are limited to lowercase letters, numbers, dots, dashes, and underscores"),
@@ -112,6 +117,12 @@ void testParseFromSpiffeIdWithPath_extractsTrustDomain() {
         assertEquals("example.org", trustDomain.getName());
     }
 
+    @Test
+    void testParseFromSpiffeIdWithPath_mixedCaseSchemeAndTrustDomain_normalizesTrustDomain() {
+        TrustDomain trustDomain = TrustDomain.parse("SpIfFe://ExAmPlE.OrG/foo");
+        assertEquals("example.org", trustDomain.getName());
+    }
+
     @Test
     void testParseInvalidScheme_spiffeWithSingleSlash_throwsInvalidScheme() {
         assertThrows(InvalidSpiffeIdException.class,