diff --git a/CHANGELOG.md b/CHANGELOG.md
index eb34210..6d5e6e0 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,4 @@
+2026-08-26 13:17 UTC — Add hover tooltips for truncated sidebar titles
 2026-08-26 13:12 UTC — Add course outline sidebar to the lesson page
 2026-08-25 12:25 UTC — Remove unreliable duplicate-lesson-file matching
 2026-08-25 00:33 UTC — Widen thumbnail sampling window past platform bumpers
diff --git a/VERSION b/VERSION
index 159c086..43dccd4 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-2026-08-26 13:12 UTC — add course outline sidebar to the lesson page
+2026-08-26 13:17 UTC — add hover tooltips for truncated sidebar titles
diff --git a/templates/_course_tree.html b/templates/_course_tree.html
index 9f5120e..d87372c 100644
--- a/templates/_course_tree.html
+++ b/templates/_course_tree.html
@@ -22,7 +22,7 @@
     <div class="tree-header directory" onclick="toggleTree(this)">
         <div class="tree-title">
             <span class="tree-icon">{{ icons.icon('folder', 16) }}</span>
-            <span class="tree-name">{{ node.name }}</span>
+            <span class="tree-name" title="{{ node.name }}">{{ node.name }}</span>
             <span class="tree-stats">
                 {% if stats.total_lessons %}{{ stats.completed_lessons }}/{{ stats.total_lessons }} watched{% else %}Empty{% endif %}
             </span>
@@ -52,7 +52,7 @@
                     {% elif lesson.lesson_type == 'mixed' %}{{ icons.icon('package', 16) }}
                     {% else %}{{ icons.icon('file-text', 16) }}{% endif %}
                 </span>
-                <span class="lesson-name">{{ lesson.title }}</span>
+                <span class="lesson-name" title="{{ lesson.title }}">{{ lesson.title }}</span>
             </div>
             <div class="lesson-meta">
                 <span class="lesson-type {{ lesson.lesson_type }}">{{ lesson.lesson_type|title }}</span>