diff --git a/zap/src/main/java/org/parosproxy/paros/network/HttpMessage.java b/zap/src/main/java/org/parosproxy/paros/network/HttpMessage.java
index 4f2497aecd1..e843ac35a11 100644
--- a/zap/src/main/java/org/parosproxy/paros/network/HttpMessage.java
+++ b/zap/src/main/java/org/parosproxy/paros/network/HttpMessage.java
@@ -66,6 +66,7 @@
 package org.parosproxy.paros.network;
 
 import java.net.HttpCookie;
+import java.nio.charset.Charset;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -504,7 +505,9 @@ private static void setBodyCharset(HttpBody body, HttpHeader header) {
         String charset = header.getCharset();
         body.setCharset(charset);
 
-        if (charset != null && !charset.equalsIgnoreCase(body.getCharset())) {
+        if (charset != null
+                && !charset.equalsIgnoreCase(body.getCharset())
+                && !isCharsetSupported(charset)) {
             LOGGER.warn(
                     "Failed to set charset {} from content-type value: {}",
                     charset,
@@ -512,6 +515,14 @@ private static void setBodyCharset(HttpBody body, HttpHeader header) {
         }
     }
 
+    private static boolean isCharsetSupported(String charset) {
+        try {
+            return Charset.isSupported(charset);
+        } catch (IllegalArgumentException ignore) {
+            return false;
+        }
+    }
+
     /**
      * Sets the given string body as the response body.
      *
diff --git a/zap/src/test/java/org/parosproxy/paros/network/HttpMessageUnitTest.java b/zap/src/test/java/org/parosproxy/paros/network/HttpMessageUnitTest.java
index bdb45d01c4b..151cf27e150 100644
--- a/zap/src/test/java/org/parosproxy/paros/network/HttpMessageUnitTest.java
+++ b/zap/src/test/java/org/parosproxy/paros/network/HttpMessageUnitTest.java
@@ -21,8 +21,10 @@
 
 import static java.util.Arrays.asList;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.empty;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.hasSize;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 import static org.hamcrest.Matchers.nullValue;
@@ -39,6 +41,10 @@
 import java.util.List;
 import java.util.stream.Stream;
 import org.apache.commons.httpclient.URI;
+import org.apache.logging.log4j.Level;
+import org.apache.logging.log4j.core.Logger;
+import org.apache.logging.log4j.core.LoggerContext;
+import org.apache.logging.log4j.core.config.Configurator;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
@@ -55,14 +61,18 @@
 import org.zaproxy.zap.network.HttpEncodingGzip;
 import org.zaproxy.zap.network.HttpRequestBody;
 import org.zaproxy.zap.network.HttpResponseBody;
+import org.zaproxy.zap.testutils.Log4jTestAppender;
 import org.zaproxy.zap.users.User;
 
 /** Unit test for {@link HttpMessage}. */
 class HttpMessageUnitTest {
 
+    private Log4jTestAppender testAppender;
+
     @AfterEach
-    void cleanUp() {
+    void cleanUp() throws Exception {
         HttpMessage.setContentEncodingsHandler(null);
+        Configurator.reconfigure(getClass().getResource("/log4j2-test.properties").toURI());
     }
 
     @Test
@@ -577,23 +587,52 @@ void shouldNotBeWebSocketUpgradeIfResponseMissUpgradeHeader() throws Exception {
     @ParameterizedTest
     @MethodSource(value = "setBodyData")
     void shouldUseContentTypeCharsetWhenSettingRequestBody(
-            String charset, String body, String expectedBody) throws Exception {
+            String charset, String expectedCharset, String body, String expectedBody)
+            throws Exception {
         // Given
         HttpMessage message = new HttpMessage();
         message.setRequestHeader(
                 new HttpRequestHeader(
                         "GET / HTTP/1.1\r\nContent-Type: text/plain; charset=" + charset));
+        withLoggerAppender();
         // When
         message.setRequestBody(body);
         // Then
-        assertThat(message.getRequestBody().getCharset(), is(equalTo(charset)));
+        assertThat(message.getRequestBody().getCharset(), is(equalTo(expectedCharset)));
         assertThat(message.getRequestBody().toString(), is(equalTo(expectedBody)));
+        assertThat(testAppender.getLogEvents(), hasSize(0));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"unknown", "!~invalid~name~"})
+    void shouldUseDefaultAndWarnOnUnknownCharsetWhenSettingRequestBody(String charset)
+            throws Exception {
+        // Given
+        HttpMessage message = new HttpMessage();
+        message.setRequestHeader(
+                new HttpRequestHeader(
+                        "GET / HTTP/1.1\r\nContent-Type: text/plain; charset=" + charset));
+        withLoggerAppender();
+        // When
+        message.setRequestBody("Body");
+        // Then
+        assertThat(message.getRequestBody().getCharset(), is(equalTo("ISO-8859-1")));
+        assertThat(message.getRequestBody().toString(), is(equalTo("Body")));
+        assertThat(testAppender.getLogEvents(), hasSize(1));
+        assertThat(
+                testAppender.getLogEvents().get(0).getMessage(),
+                containsString("Failed to set charset"));
     }
 
     static Stream<Arguments> setBodyData() {
+        String iso8851 = StandardCharsets.ISO_8859_1.name();
+        String utf8 = StandardCharsets.UTF_8.name();
         return Stream.of(
-                arguments(StandardCharsets.ISO_8859_1.name(), "J/ψ → VP", "J/????VP"),
-                arguments(StandardCharsets.UTF_8.name(), "J/ψ → VP", "J/ψ → VP"));
+                arguments(iso8851, iso8851, "J/ψ → VP", "J/????VP"),
+                arguments(utf8, utf8, "J/ψ → VP", "J/ψ → VP"),
+                // Check aliases work as well and don't cause warns
+                arguments("ISO_8859-1:1987", iso8851, "J/ψ → VP", "J/????VP"),
+                arguments("utf8", utf8, "J/ψ → VP", "J/ψ → VP"));
     }
 
     static Stream<Arguments> getNonPostMethods() {
@@ -605,17 +644,41 @@ static Stream<Arguments> getNonPostMethods() {
     @ParameterizedTest
     @MethodSource(value = "setBodyData")
     void shouldUseContentTypeCharsetWhenSettingResponseBody(
-            String charset, String body, String expectedBody) throws Exception {
+            String charset, String expectedCharset, String body, String expectedBody)
+            throws Exception {
         // Given
         HttpMessage message = new HttpMessage();
         message.setResponseHeader(
                 new HttpResponseHeader(
                         "HTTP/1.1 200 OK\r\nContent-Type: text/plain; charset=" + charset));
+        withLoggerAppender();
         // When
         message.setResponseBody(body);
         // Then
-        assertThat(message.getResponseBody().getCharset(), is(equalTo(charset)));
+        assertThat(message.getResponseBody().getCharset(), is(equalTo(expectedCharset)));
         assertThat(message.getResponseBody().toString(), is(equalTo(expectedBody)));
+        assertThat(testAppender.getLogEvents(), hasSize(0));
+    }
+
+    @ParameterizedTest
+    @ValueSource(strings = {"unknown", "!~invalid~name~"})
+    void shouldUseDefaultAndWarnOnUnknownCharsetWhenSettingResponseBody(String charset)
+            throws Exception {
+        // Given
+        HttpMessage message = new HttpMessage();
+        message.setResponseHeader(
+                new HttpResponseHeader(
+                        "HTTP/1.1 200 OK\r\nContent-Type: text/plain; charset=" + charset));
+        withLoggerAppender();
+        // When
+        message.setResponseBody("Body");
+        // Then
+        assertThat(message.getResponseBody().getCharset(), is(equalTo("UTF-8")));
+        assertThat(message.getResponseBody().toString(), is(equalTo("Body")));
+        assertThat(testAppender.getLogEvents(), hasSize(1));
+        assertThat(
+                testAppender.getLogEvents().get(0).getMessage(),
+                containsString("Failed to set charset"));
     }
 
     private static HttpMessage newHttpMessage() throws Exception {
@@ -644,4 +707,12 @@ private static List<HttpEncoding> encodings(HttpBody body) {
         verify(body).setContentEncodings(arg.capture());
         return arg.getValue();
     }
+
+    private void withLoggerAppender() {
+        testAppender = new Log4jTestAppender();
+        LoggerContext context = LoggerContext.getContext();
+        Logger logger = context.getLogger(HttpMessage.class.getCanonicalName());
+        context.getConfiguration().addLoggerAppender(logger, testAppender);
+        logger.setLevel(Level.WARN);
+    }
 }