diff --git a/spring-core/src/main/java/org/springframework/util/MimeType.java b/spring-core/src/main/java/org/springframework/util/MimeType.java
index f4ca7953ed..ccfd56ada9 100644
--- a/spring-core/src/main/java/org/springframework/util/MimeType.java
+++ b/spring-core/src/main/java/org/springframework/util/MimeType.java
@@ -25,6 +25,7 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Locale;
 import java.util.Map;
+import java.util.Map.Entry;
 import java.util.TreeSet;
 
 /**
@@ -430,7 +431,37 @@ public class MimeType implements Comparable<MimeType>, Serializable {
 		MimeType otherType = (MimeType) other;
 		return (this.type.equalsIgnoreCase(otherType.type) &&
 				this.subtype.equalsIgnoreCase(otherType.subtype) &&
-				this.parameters.equals(otherType.parameters));
+				parametersAreEqual(otherType));
+	}
+
+	/**
+	 * Determine if the parameters in this {@code MimeType} and the supplied
+	 * {@code MimeType} are equal, performing case-insensitive comparisons
+	 * for {@link Charset}s.
+	 * @since 4.2
+	 */
+	private boolean parametersAreEqual(MimeType that) {
+		if (this.parameters.size() != that.parameters.size()) {
+			return false;
+		}
+
+		for (Entry<String, String> entry : this.parameters.entrySet()) {
+			String key = entry.getKey();
+			if (!that.parameters.containsKey(key)) {
+				return false;
+			}
+
+			if (PARAM_CHARSET.equals(key)) {
+				if (!ObjectUtils.nullSafeEquals(this.getCharSet(), that.getCharSet())) {
+					return false;
+				}
+			}
+			else if (!ObjectUtils.nullSafeEquals(this.parameters.get(key), that.parameters.get(key))) {
+				return false;
+			}
+		}
+
+		return true;
 	}
 
 	@Override
diff --git a/spring-core/src/test/java/org/springframework/util/MimeTypeTests.java b/spring-core/src/test/java/org/springframework/util/MimeTypeTests.java
index da7d9c1178..b9d3480fd7 100644
--- a/spring-core/src/test/java/org/springframework/util/MimeTypeTests.java
+++ b/spring-core/src/test/java/org/springframework/util/MimeTypeTests.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * Copyright 2002-2015 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,15 +27,18 @@ import org.junit.Test;
 import org.springframework.core.convert.ConversionService;
 import org.springframework.core.convert.support.DefaultConversionService;
 
+import static java.util.Collections.singletonMap;
 import static org.junit.Assert.*;
 
 /**
+ * Unit tests for {@link MimeType}.
+ *
  * @author Arjen Poutsma
  * @author Juergen Hoeller
+ * @author Sam Brannen
  */
 public class MimeTypeTests {
 
-
 	@Test(expected = IllegalArgumentException.class)
 	public void slashInSubtype() {
 		new MimeType("text", "/");
@@ -85,7 +88,7 @@ public class MimeTypeTests {
 	}
 
 	@Test
-	public void testWithConversionService() {
+	public void withConversionService() {
 		ConversionService conversionService = new DefaultConversionService();
 		assertTrue(conversionService.canConvert(String.class, MimeType.class));
 		MimeType mimeType = MimeType.valueOf("application/xml");
@@ -211,16 +214,18 @@ public class MimeTypeTests {
 		MimeTypeUtils.parseMimeType("text/html; charset=foo-bar");
 	}
 
-	// SPR-8917
-
+	/**
+	 * SPR-8917
+	 */
 	@Test
 	public void parseMimeTypeQuotedParameterValue() {
 		MimeType mimeType = MimeTypeUtils.parseMimeType("audio/*;attr=\"v>alue\"");
 		assertEquals("\"v>alue\"", mimeType.getParameter("attr"));
 	}
 
-	// SPR-8917
-
+	/**
+	 * SPR-8917
+	 */
 	@Test
 	public void parseMimeTypeSingleQuotedParameterValue() {
 		MimeType mimeType = MimeTypeUtils.parseMimeType("audio/*;attr='v>alue'");
@@ -249,7 +254,7 @@ public class MimeTypeTests {
 		MimeType audioBasic = new MimeType("audio", "basic");
 		MimeType audio = new MimeType("audio");
 		MimeType audioWave = new MimeType("audio", "wave");
-		MimeType audioBasicLevel = new MimeType("audio", "basic", Collections.singletonMap("level", "1"));
+		MimeType audioBasicLevel = new MimeType("audio", "basic", singletonMap("level", "1"));
 
 		// equal
 		assertEquals("Invalid comparison result", 0, audioBasic.compareTo(audioBasic));
@@ -284,16 +289,27 @@ public class MimeTypeTests {
 		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
 		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
 
-		m1 = new MimeType("audio", "basic", Collections.singletonMap("foo", "bar"));
-		m2 = new MimeType("audio", "basic", Collections.singletonMap("Foo", "bar"));
+		m1 = new MimeType("audio", "basic", singletonMap("foo", "bar"));
+		m2 = new MimeType("audio", "basic", singletonMap("Foo", "bar"));
 		assertEquals("Invalid comparison result", 0, m1.compareTo(m2));
 		assertEquals("Invalid comparison result", 0, m2.compareTo(m1));
 
-		m1 = new MimeType("audio", "basic", Collections.singletonMap("foo", "bar"));
-		m2 = new MimeType("audio", "basic", Collections.singletonMap("foo", "Bar"));
+		m1 = new MimeType("audio", "basic", singletonMap("foo", "bar"));
+		m2 = new MimeType("audio", "basic", singletonMap("foo", "Bar"));
 		assertTrue("Invalid comparison result", m1.compareTo(m2) != 0);
 		assertTrue("Invalid comparison result", m2.compareTo(m1) != 0);
 	}
 
+	/**
+	 * SPR-13157
+	 * @since 4.2
+	 */
+	@Test
+	public void equalsIsCaseInsensitiveForCharsets() {
+		MimeType m1 = new MimeType("text", "plain", singletonMap("charset", "UTF-8"));
+		MimeType m2 = new MimeType("text", "plain", singletonMap("charset", "utf-8"));
+		assertEquals(m1, m2);
+		assertEquals(m2, m1);
+	}
 
 }
diff --git a/spring-web/src/test/java/org/springframework/web/client/AbstractJettyServerTestCase.java b/spring-web/src/test/java/org/springframework/web/client/AbstractJettyServerTestCase.java
index f633dec43e..5f54060ba9 100644
--- a/spring-web/src/test/java/org/springframework/web/client/AbstractJettyServerTestCase.java
+++ b/spring-web/src/test/java/org/springframework/web/client/AbstractJettyServerTestCase.java
@@ -56,7 +56,7 @@ public class AbstractJettyServerTestCase {
 
 	protected static final String baseUrl = "http://localhost:" + port;
 
-	protected static final MediaType textContentType = new MediaType("text", "plain", Collections.singletonMap("charset", "utf-8"));
+	protected static final MediaType textContentType = new MediaType("text", "plain", Collections.singletonMap("charset", "UTF-8"));
 
 	protected static final MediaType jsonContentType = new MediaType("application", "json", Collections.singletonMap("charset", "utf-8"));