diff --git a/org.eclipse.lsp4e/plugin.properties b/org.eclipse.lsp4e/plugin.properties
index fb37129e2..2a49a4359 100644
--- a/org.eclipse.lsp4e/plugin.properties
+++ b/org.eclipse.lsp4e/plugin.properties
@@ -26,6 +26,8 @@ notification.category.label = LSP
 notification.event.label = LSP Notification
 command.toggle.highlight.label = Toggle Mark Occurrences
 command.toggle.highlight.name = Toggle Highlight
+command.toggle.outline.collapseAll.name = Collapse All
+command.toggle.outline.collapseAll.label = Collapse All
 command.toggle.outline.sort.name = Sort
 command.toggle.outline.sort.label = Sort
 command.toggle.outline.hideFields.name = Hide Fields
diff --git a/org.eclipse.lsp4e/plugin.xml b/org.eclipse.lsp4e/plugin.xml
index 875b7e10c..8339ddda6 100644
--- a/org.eclipse.lsp4e/plugin.xml
+++ b/org.eclipse.lsp4e/plugin.xml
@@ -734,6 +734,10 @@
 
    <!-- outline: define commands -->
    <extension point="org.eclipse.ui.commands">
+      <command
+            categoryId="org.eclipse.lsp4e.category"
+            id="org.eclipse.lsp4e.collapseAllOutline"
+            name="%command.toggle.outline.collapseAll.name" />
       <command
             categoryId="org.eclipse.lsp4e.category"
             id="org.eclipse.lsp4e.toggleSortOutline"
@@ -770,6 +774,9 @@
 
    <!-- outline: register command handlers -->
    <extension point="org.eclipse.ui.handlers">
+      <handler commandId="org.eclipse.lsp4e.collapseAllOutline">
+         <class class="org.eclipse.lsp4e.outline.CollapseAllOutlineHandler" />
+      </handler>
       <handler commandId="org.eclipse.lsp4e.toggleSortOutline">
          <class class="org.eclipse.lsp4e.outline.ToggleSortOutlineHandler" />
       </handler>
@@ -786,6 +793,10 @@
 
    <!-- outline: command images -->
    <extension point="org.eclipse.ui.commandImages">
+      <image
+            commandId="org.eclipse.lsp4e.collapseAllOutline"
+            disabledIcon="platform:/plugin/org.eclipse.jdt.ui/icons/full/dlcl16/collapseall.png"
+            icon="platform:/plugin/org.eclipse.jdt.ui/icons/full/elcl16/collapseall.png" />
       <image
             commandId="org.eclipse.lsp4e.toggleSortOutline"
             disabledIcon="icons/full/dlcl16/alphab_sort_co.png"
@@ -805,6 +816,19 @@
       <menuContribution
              allPopups="false"
              locationURI="toolbar:org.eclipse.ui.views.ContentOutline?after=additions">
+         <command
+               commandId="org.eclipse.lsp4e.collapseAllOutline"
+               id="org.eclipse.lsp4e.outline.toolbar.collapseAll"
+               label="%command.toggle.outline.collapseAll.label"
+               style="push">
+            <visibleWhen>
+               <reference definitionId="org.eclipse.lsp4e.activeEditorHasCNFOutlinePage" />
+            </visibleWhen>
+         </command>
+      </menuContribution>
+      <menuContribution
+             allPopups="false"
+             locationURI="toolbar:org.eclipse.ui.views.ContentOutline?after=org.eclipse.lsp4e.outline.toolbar.collapseAll">
          <command
                commandId="org.eclipse.lsp4e.toggleSortOutline"
                id="org.eclipse.lsp4e.outline.toolbar.sort"
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java
index 5d16a0d28..1a58edf3c 100644
--- a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CNFOutlinePage.java
@@ -251,6 +251,10 @@ private static boolean isOffsetInRange(int offset, Range range, IDocument docume
 		}
 	}
 
+	public void collapseTree() {
+		outlineViewer.collapseAll();
+	}
+
 	@Override
 	public void dispose() {
 		preferences.removePreferenceChangeListener(this);
diff --git a/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CollapseAllOutlineHandler.java b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CollapseAllOutlineHandler.java
new file mode 100644
index 000000000..02a050f98
--- /dev/null
+++ b/org.eclipse.lsp4e/src/org/eclipse/lsp4e/outline/CollapseAllOutlineHandler.java
@@ -0,0 +1,32 @@
+/*******************************************************************************
+ * Copyright (c) 2025 Vegard IT GmbH and others.
+ * This program and the accompanying materials are made
+ * available under the terms of the Eclipse Public License 2.0
+ * which is available at https://www.eclipse.org/legal/epl-2.0/
+ *
+ * SPDX-License-Identifier: EPL-2.0
+ *
+ * Contributors:
+ *  Sebastian Thomschke (Vegard IT GmbH) - initial implementation.
+ *******************************************************************************/
+package org.eclipse.lsp4e.outline;
+
+import org.eclipse.core.commands.AbstractHandler;
+import org.eclipse.core.commands.ExecutionEvent;
+import org.eclipse.jdt.annotation.Nullable;
+import org.eclipse.lsp4e.ui.UI;
+import org.eclipse.ui.views.contentoutline.ContentOutline;
+
+public class CollapseAllOutlineHandler extends AbstractHandler {
+
+	@Override
+	public @Nullable Object execute(ExecutionEvent event) {
+		final var workbenchPage = UI.getActivePage();
+		if (workbenchPage != null //
+				&& workbenchPage.getActivePart() instanceof ContentOutline outline
+				&& outline.getCurrentPage() instanceof CNFOutlinePage page) {
+			page.collapseTree();
+		}
+		return null;
+	}
+}