diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/HttpConfigTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/HttpConfigTest.java
index a5f98ee..5336dd7 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/HttpConfigTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/transport/HttpConfigTest.java
@@ -13,7 +13,9 @@
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
 
+import org.eclipse.jgit.junit.MockSystemReader;
 import org.eclipse.jgit.lib.Config;
+import org.eclipse.jgit.util.SystemReader;
 import org.junit.Before;
 import org.junit.Test;
 
@@ -96,7 +98,8 @@
 	@Test
 	public void testMatchWithInvalidUriInConfig() throws Exception {
 		config.fromText(
-				DEFAULT + "[http \"///\"]\n" + "\tpostBuffer = 1024\n");
+				DEFAULT + "[http \"///#expectedWarning\"]\n"
+						+ "\tpostBuffer = 1024\n");
 		HttpConfig http = new HttpConfig(config,
 				new URIish("http://example.com/path/repo.git"));
 		assertEquals(1, http.getPostBuffer());
@@ -104,7 +107,8 @@
 
 	@Test
 	public void testMatchWithInvalidAndValidUriInConfig() throws Exception {
-		config.fromText(DEFAULT + "[http \"///\"]\n" + "\tpostBuffer = 1024\n"
+		config.fromText(DEFAULT + "[http \"///#expectedWarning\"]\n"
+				+ "\tpostBuffer = 1024\n"
 				+ "[http \"http://example.com\"]\n" + "\tpostBuffer = 2048\n");
 		HttpConfig http = new HttpConfig(config,
 				new URIish("http://example.com/path/repo.git"));
@@ -232,6 +236,31 @@
 	}
 
 	@Test
+	public void testUserAgentEnvOverride() throws Exception {
+		String mockAgent = "jgit-test/5.10.0";
+		SystemReader originalReader = SystemReader.getInstance();
+		SystemReader.setInstance(new MockSystemReader() {
+
+			@Override
+			public String getenv(String variable) {
+				if ("GIT_HTTP_USER_AGENT".equals(variable)) {
+					return mockAgent;
+				}
+				return super.getenv(variable);
+			}
+		});
+		try {
+			config.fromText(DEFAULT + "[http \"http://example.com\"]\n"
+					+ "\tuserAgent=DummyAgent/4.0\n");
+			HttpConfig http = new HttpConfig(config,
+					new URIish("http://example.com/"));
+			assertEquals(mockAgent, http.getUserAgent());
+		} finally {
+			SystemReader.setInstance(originalReader);
+		}
+	}
+
+	@Test
 	public void testUserAgentNonAscii() throws Exception {
 		config.fromText(DEFAULT + "[http \"http://example.com\"]\n"
 				+ "\tuserAgent= d ümmy Agent -5.10\n");
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/HttpConfig.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/HttpConfig.java
index 58fc250..dc82f46 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/HttpConfig.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/HttpConfig.java
@@ -121,6 +121,8 @@
 		}
 	}).get().intValue();
 
+	private static final String ENV_HTTP_USER_AGENT = "GIT_HTTP_USER_AGENT"; //$NON-NLS-1$
+
 	/**
 	 * Config values for http.followRedirect.
 	 */
@@ -364,6 +366,11 @@
 			saveCookies = config.getBoolean(HTTP, match, SAVE_COOKIES_KEY,
 					saveCookies);
 		}
+		// Environment overrides config
+		agent = SystemReader.getInstance().getenv(ENV_HTTP_USER_AGENT);
+		if (!StringUtils.isEmptyOrNull(agent)) {
+			userAgent = UserAgent.clean(agent);
+		}
 		postBuffer = postBufferSize;
 		sslVerify = sslVerifyFlag;
 		followRedirects = followRedirectsMode;