diff --git a/addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js b/addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js
index 0b31d685568..5b69160db6a 100644
--- a/addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js
+++ b/addons/web_editor/static/src/js/editor/odoo-editor/src/OdooEditor.js
@@ -711,6 +711,19 @@ export class OdooEditor extends EventTarget {
             return false;
         }
 
+        // If the common ancestor is in a nested list, make sure to sanitize
+        // that list's parent <li> instead, so there is enough context to
+        // potentially merge sibling nested lists
+        // (eg, <ol>
+        //          <li class="oe-nested"><ul>...</ul></li>
+        //          <li class="oe-nested"><ul>...</ul></li>
+        //      </ol>: these two lists should be merged together so the common
+        // ancestor should be the <ol> element).
+        const nestedListAncestor = closestElement(commonAncestor, '.oe-nested');
+        if (nestedListAncestor && nestedListAncestor.parentElement) {
+            commonAncestor = nestedListAncestor.parentElement;
+        }
+
         // sanitize and mark current position as sanitized
         sanitize(commonAncestor);
         this._pluginCall('sanitizeElement', [commonAncestor]);
diff --git a/addons/web_editor/static/src/js/editor/odoo-editor/test/spec/list.test.js b/addons/web_editor/static/src/js/editor/odoo-editor/test/spec/list.test.js
index d0ca544fbdc..fbd516d9e51 100644
--- a/addons/web_editor/static/src/js/editor/odoo-editor/test/spec/list.test.js
+++ b/addons/web_editor/static/src/js/editor/odoo-editor/test/spec/list.test.js
@@ -315,6 +315,17 @@ describe('List', () => {
                                     </li>
                                 </ul>`),
                             stepFunction: toggleCheckList,
+                            contentAfterEdit: unformat(`
+                                <ul class="o_checklist">
+                                    <li class="o_checked" id="checkId-1">abc</li>
+                                    <li class="oe-nested">
+                                        <ul class="o_checklist">
+                                            <li class="o_checked" id="checkId-2">def</li>
+                                            <li id="checkId-4">g[]hi</li>
+                                            <li class="o_checked" id="checkId-3">jkl</li>
+                                        </ul>
+                                    </li>
+                                </ul>`),
                             contentAfter: unformat(`
                                 <ul class="o_checklist">
                                     <li class="o_checked">abc</li>