diff --git a/server/channels/app/channel.go b/server/channels/app/channel.go
index 2a5b05bae8d..15b6a5033e9 100644
--- a/server/channels/app/channel.go
+++ b/server/channels/app/channel.go
@@ -697,6 +697,9 @@ func (a *App) UpdateChannel(c request.CTX, channel *model.Channel) (*model.Chann
 		var invErr *store.ErrInvalidInput
 		switch {
 		case errors.As(err, &invErr):
+			if invErr.Entity == "Channel" && invErr.Field == "Name" {
+				return nil, model.NewAppError("UpdateChannel", store.ChannelExistsError, nil, "", http.StatusBadRequest).Wrap(err)
+			}
 			return nil, model.NewAppError("UpdateChannel", "app.channel.update.bad_id", nil, "", http.StatusBadRequest).Wrap(err)
 		case errors.As(err, &appErr):
 			return nil, appErr
diff --git a/webapp/channels/src/components/channel_name_form_field/channel_name_form_field.tsx b/webapp/channels/src/components/channel_name_form_field/channel_name_form_field.tsx
index 508dd40f071..ae9d9f7fe9b 100644
--- a/webapp/channels/src/components/channel_name_form_field/channel_name_form_field.tsx
+++ b/webapp/channels/src/components/channel_name_form_field/channel_name_form_field.tsx
@@ -26,6 +26,7 @@ export type Props = {
     autoFocus?: boolean;
     onErrorStateChange?: (isError: boolean) => void;
     team?: Team;
+    urlError?: string;
 }
 
 import './channel_name_form_field.scss';
@@ -139,7 +140,7 @@ const ChannelNameFormField = (props: Props): JSX.Element => {
                 pathInfo={url}
                 limit={Constants.MAX_CHANNELNAME_LENGTH}
                 shortenLength={Constants.DEFAULT_CHANNELURL_SHORTEN_LENGTH}
-                error={urlError}
+                error={urlError || props.urlError}
                 onChange={handleOnURLChange}
             />
         </React.Fragment>
diff --git a/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.test.tsx b/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.test.tsx
index 4f4d6809098..024452c0667 100644
--- a/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.test.tsx
+++ b/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.test.tsx
@@ -175,4 +175,43 @@ describe('component/ConvertGmToChannelModal', () => {
             fireEvent.click(confirmButton!);
         });
     });
+
+    test('duplicate channel names should npt be allowed', async () => {
+        TestHelper.initBasic(Client4);
+
+        nock(Client4.getBaseRoute()).
+            get('/channels/channel_id_1/common_teams').
+            reply(200, [
+                {id: 'team_id_1', display_name: 'Team 1', name: 'team_1'},
+            ]);
+
+        baseProps.actions.convertGroupMessageToPrivateChannel.mockResolvedValueOnce({
+            error: {
+                server_error_id: 'store.sql_channel.save_channel.exists.app_error',
+            },
+        });
+
+        renderWithFullContext(
+            <ConvertGmToChannelModal {...baseProps}/>,
+            baseState,
+        );
+
+        await waitFor(
+            () => expect(screen.queryByText('Conversation history will be visible to any channel members')).toBeInTheDocument(),
+            {timeout: 1500},
+        );
+
+        const channelNameInput = screen.queryByPlaceholderText('Channel name');
+        expect(channelNameInput).toBeInTheDocument();
+        fireEvent.change(channelNameInput!, {target: {value: 'Channel'}});
+
+        const confirmButton = screen.queryByText('Convert to private channel');
+        expect(channelNameInput).toBeInTheDocument();
+
+        await act(async () => {
+            fireEvent.click(confirmButton!);
+        });
+
+        expect(screen.queryByText('A channel with that URL already exists')).toBeInTheDocument();
+    });
 });
diff --git a/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.tsx b/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.tsx
index 8a53832e4e9..774c7465133 100644
--- a/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.tsx
+++ b/webapp/channels/src/components/convert_gm_to_channel_modal/convert_gm_to_channel_modal.tsx
@@ -28,6 +28,10 @@ import TeamSelector from 'components/convert_gm_to_channel_modal/team_selector/t
 import WarningTextSection from 'components/convert_gm_to_channel_modal/warning_text_section/warning_text_section';
 import LoadingSpinner from 'components/widgets/loading/loading_spinner';
 
+const enum ServerErrorId {
+    CHANNEL_NAME_EXISTS = 'store.sql_channel.save_channel.exists.app_error',
+}
+
 export type Props = {
     onExited: () => void;
     channel: Channel;
@@ -43,8 +47,11 @@ const ConvertGmToChannelModal = (props: Props) => {
 
     const [channelName, setChannelName] = useState<string>('');
     const channelURL = useRef<string>('');
+
+    const [urlError, setURLError] = useState('');
     const handleChannelURLChange = useCallback((newURL: string) => {
         channelURL.current = newURL;
+        setURLError('');
     }, []);
 
     const [channelMemberNames, setChannelMemberNames] = useState<string[]>([]);
@@ -112,7 +119,17 @@ const ConvertGmToChannelModal = (props: Props) => {
         const {error} = await props.actions.convertGroupMessageToPrivateChannel(props.channel.id, selectedTeamId, channelName.trim(), channelURL.current.trim());
 
         if (error) {
-            setConversionError(error.message);
+            if (error.server_error_id === ServerErrorId.CHANNEL_NAME_EXISTS) {
+                setURLError(
+                    formatMessage({
+                        id: 'channel_modal.alreadyExist',
+                        defaultMessage: 'A channel with that URL already exists',
+                    }),
+                );
+            } else {
+                setConversionError(error.message);
+            }
+
             return;
         }
 
@@ -122,7 +139,7 @@ const ConvertGmToChannelModal = (props: Props) => {
     }, [selectedTeamId, props.channel.id, channelName, channelURL.current, props.actions.moveChannelsInSidebar]);
 
     const showLoader = !commonTeamsFetched || !loadingAnimationTimeout;
-    const canCreate = selectedTeamId !== undefined && channelName !== '' && !nameError;
+    const canCreate = selectedTeamId !== undefined && channelName !== '' && !nameError && !urlError;
     const modalProps: Partial<ComponentProps<typeof GenericModal>> = {};
     let modalBody;
 
@@ -171,6 +188,7 @@ const ConvertGmToChannelModal = (props: Props) => {
                         onURLChange={handleChannelURLChange}
                         onErrorStateChange={setNameError}
                         team={selectedTeamId ? commonTeamsById[selectedTeamId] : undefined}
+                        urlError={urlError}
                     />
 
                     {
diff --git a/webapp/channels/src/components/new_channel_modal/new_channel_modal.scss b/webapp/channels/src/components/new_channel_modal/new_channel_modal.scss
index bbc08073272..2f276fe004d 100644
--- a/webapp/channels/src/components/new_channel_modal/new_channel_modal.scss
+++ b/webapp/channels/src/components/new_channel_modal/new_channel_modal.scss
@@ -81,7 +81,3 @@
         font-weight: 500;
     }
 }
-
-.new-channel-modal__url {
-    margin-top: 4px;
-}
diff --git a/webapp/channels/src/components/new_channel_modal/new_channel_modal.tsx b/webapp/channels/src/components/new_channel_modal/new_channel_modal.tsx
index 1e93b35662b..0b5966943d1 100644
--- a/webapp/channels/src/components/new_channel_modal/new_channel_modal.tsx
+++ b/webapp/channels/src/components/new_channel_modal/new_channel_modal.tsx
@@ -83,6 +83,11 @@ const NewChannelModal = () => {
     const [canCreateFromPluggable, setCanCreateFromPluggable] = useState(true);
     const [actionFromPluggable, setActionFromPluggable] = useState<((currentTeamId: string, channelId: string) => Promise<Board>) | undefined>(undefined);
 
+    const handleURLChange = useCallback((newURL: string) => {
+        setURL(newURL);
+        setURLError('');
+    }, []);
+
     const handleOnModalConfirm = async () => {
         if (!canCreate) {
             return;
@@ -265,8 +270,9 @@ const NewChannelModal = () => {
                     name='new-channel-modal-name'
                     placeholder={formatMessage({id: 'channel_modal.name.placeholder', defaultMessage: 'Enter a name for your new channel'})}
                     onDisplayNameChange={setDisplayName}
-                    onURLChange={setURL}
+                    onURLChange={handleURLChange}
                     onErrorStateChange={setChannelInputError}
+                    urlError={urlError}
                 />
                 <PublicPrivateSelector
                     className='new-channel-modal-type-selector'
diff --git a/webapp/channels/src/components/widgets/inputs/url_input/url_input.scss b/webapp/channels/src/components/widgets/inputs/url_input/url_input.scss
index 4fed431bed5..28b2c8256c6 100644
--- a/webapp/channels/src/components/widgets/inputs/url_input/url_input.scss
+++ b/webapp/channels/src/components/widgets/inputs/url_input/url_input.scss
@@ -11,6 +11,7 @@
         display: flex;
         min-height: 32px;
         align-items: center;
+        margin-top: 4px;
 
         .url-input-label {
             flex: none;