diff --git a/greenmail-core/src/main/java/com/icegreen/greenmail/imap/commands/CommandParser.java b/greenmail-core/src/main/java/com/icegreen/greenmail/imap/commands/CommandParser.java
index 4fd07f567e..712b429146 100644
--- a/greenmail-core/src/main/java/com/icegreen/greenmail/imap/commands/CommandParser.java
+++ b/greenmail-core/src/main/java/com/icegreen/greenmail/imap/commands/CommandParser.java
@@ -85,7 +85,7 @@ public String string(ImapRequestLineReader request, Charset charset) throws Prot
             case '{':
                 return new String(consumeLiteralAsBytes(request), charset);
             default:
-                return consumeWord(request);
+                return consumeWordOnly(request, chr -> chr != ')');
         }
     }
 
diff --git a/greenmail-core/src/test/java/com/icegreen/greenmail/imap/commands/SearchCommandParserTest.java b/greenmail-core/src/test/java/com/icegreen/greenmail/imap/commands/SearchCommandParserTest.java
index bae8c39431..649974317a 100644
--- a/greenmail-core/src/test/java/com/icegreen/greenmail/imap/commands/SearchCommandParserTest.java
+++ b/greenmail-core/src/test/java/com/icegreen/greenmail/imap/commands/SearchCommandParserTest.java
@@ -69,6 +69,16 @@ public void testAndSubjectOrToFrom() throws ProtocolException, AddressException
         assertThat(searchTerm).isEqualTo(expectedTerm);
     }
 
+    @Test
+    public void testNotKeyword() throws ProtocolException {
+        Flags flags = new Flags();
+        flags.add("ABC");
+		SearchTerm expectedTerm = new NotTerm(new FlagTerm(flags, true));
+        SearchTerm searchTerm = parse("NOT (KEYWORD ABC)");
+
+        assertThat(searchTerm).isEqualTo(expectedTerm);
+    }
+
     private SearchTerm parse(String line) throws ProtocolException {
         final byte[] bytes = (line.endsWith("\n") ? line : (line + '\n')).getBytes();
         ByteArrayInputStream ins = new ByteArrayInputStream(bytes);
diff --git a/greenmail-core/src/test/java/com/icegreen/greenmail/test/commands/ImapSearchTest.java b/greenmail-core/src/test/java/com/icegreen/greenmail/test/commands/ImapSearchTest.java
index 46acea2354..a194ca80bf 100644
--- a/greenmail-core/src/test/java/com/icegreen/greenmail/test/commands/ImapSearchTest.java
+++ b/greenmail-core/src/test/java/com/icegreen/greenmail/test/commands/ImapSearchTest.java
@@ -92,6 +92,12 @@ public void testSearch() throws Exception {
             assertThat(imapMessages[1].getFlags().contains(fooFlags)).isFalse();
             assertThat(imapMessages[2].getFlags().contains(fooFlags)).isFalse();
 
+            imapMessages = imapFolder.search(new NotTerm(new FlagTerm(fooFlags, true)));
+            assertThat(imapMessages.length).isEqualTo(5);
+            assertThat(imapMessages[0].getFlags().contains(fooFlags)).isFalse();
+            assertThat(imapMessages[1].getFlags().contains(fooFlags)).isFalse();
+            assertThat(imapMessages[2].getFlags().contains(fooFlags)).isFalse();
+
             // Search header ids
             String id = m0.getHeader("Message-ID")[0];
             imapMessages = imapFolder.search(new HeaderTerm("Message-ID", id));