diff --git a/src/main/java/org/owasp/html/HtmlEntities.java b/src/main/java/org/owasp/html/HtmlEntities.java
index 08423268..6c1e6636 100644
--- a/src/main/java/org/owasp/html/HtmlEntities.java
+++ b/src/main/java/org/owasp/html/HtmlEntities.java
@@ -2232,6 +2232,7 @@ public static int appendDecodedEntity(
         case 'y': case 'z':
         case '0': case '1': case '2': case '3': case '4': case '5':
         case '6': case '7': case '8': case '9':
+        case '-': case '_':
           break;
         case '=':
           // An equal sign after an entity missing a closing semicolon should
diff --git a/src/test/java/org/owasp/html/HtmlEntitiesTest.java b/src/test/java/org/owasp/html/HtmlEntitiesTest.java
new file mode 100644
index 00000000..347cd05f
--- /dev/null
+++ b/src/test/java/org/owasp/html/HtmlEntitiesTest.java
@@ -0,0 +1,24 @@
+package org.owasp.html;
+
+import org.junit.Test;
+
+import junit.framework.TestCase;
+
+@SuppressWarnings("javadoc")
+public class HtmlEntitiesTest extends TestCase {
+
+	@Test
+	public void testAfterAmpString() {
+		String input = "<a href=\"/t?a=1&order_id=2\">order</a>";
+		String output = Encoding.decodeHtml(input);
+		assertEquals("<a href=\"/t?a=1&order_id=2\">order</a>", output);
+
+		input = "<a href=\"/t?a=1&order-id=2\">order</a>";
+		output = Encoding.decodeHtml(input);
+		assertEquals("<a href=\"/t?a=1&order-id=2\">order</a>", output);
+
+		input = "<a href=\"/t?a=1&order=2\">order</a>";
+		output = Encoding.decodeHtml(input);
+		assertEquals("<a href=\"/t?a=1&order=2\">order</a>", output);
+	}
+}
\ No newline at end of file