diff --git a/src/app/(dashboard)/courses/[courseSlug]/certificate/page.tsx b/src/app/(dashboard)/courses/[courseSlug]/certificate/page.tsx
index 3640169..de3f8b6 100644
--- a/src/app/(dashboard)/courses/[courseSlug]/certificate/page.tsx
+++ b/src/app/(dashboard)/courses/[courseSlug]/certificate/page.tsx
@@ -194,13 +194,21 @@ async function PendingLessons({
     take: 50,
   });
 
+  const lessonIds = allLessons.map((l) => l.id);
   const completedSet = new Set(
-    (
-      await db.lessonProgress.findMany({
-        where: { userId, status: 'COMPLETED', deletedAt: null },
-        select: { lessonId: true },
-      })
-    ).map((p) => p.lessonId),
+    lessonIds.length > 0
+      ? (
+          await db.lessonProgress.findMany({
+            where: {
+              userId,
+              lessonId: { in: lessonIds },
+              status: 'COMPLETED',
+              deletedAt: null,
+            },
+            select: { lessonId: true },
+          })
+        ).map((p) => p.lessonId)
+      : [],
   );
 
   const pending = allLessons.filter((l) => !completedSet.has(l.id)).slice(0, 8);
diff --git a/src/app/(dashboard)/courses/page.tsx b/src/app/(dashboard)/courses/page.tsx
index 1d0c6c3..cb18f76 100644
--- a/src/app/(dashboard)/courses/page.tsx
+++ b/src/app/(dashboard)/courses/page.tsx
@@ -37,11 +37,17 @@ export default async function CoursesIndexPage() {
     },
   });
 
-  // Get user's lesson progress
-  const lessonProgress = await db.lessonProgress.findMany({
-    where: { userId: user.id, deletedAt: null },
-    select: { lessonId: true, status: true },
-  });
+  // Get user's lesson progress (optimized: scope query to published lessons only to avoid loading full history)
+  const allPublishedLessonIds = courses.flatMap((c) =>
+    c.modules.flatMap((m) => m.lessons.map((l) => l.id))
+  );
+
+  const lessonProgress = allPublishedLessonIds.length > 0
+    ? await db.lessonProgress.findMany({
+        where: { userId: user.id, lessonId: { in: allPublishedLessonIds }, deletedAt: null },
+        select: { lessonId: true, status: true },
+      })
+    : [];
   const progressMap = new Map(lessonProgress.map((p) => [p.lessonId, p.status]));
 
   return (
diff --git a/src/app/(dashboard)/dashboard/page.tsx b/src/app/(dashboard)/dashboard/page.tsx
index 546298d..7939ee7 100644
--- a/src/app/(dashboard)/dashboard/page.tsx
+++ b/src/app/(dashboard)/dashboard/page.tsx
@@ -30,11 +30,17 @@ export default async function DashboardPage() {
     },
   });
 
-  // Get user's lesson progress
-  const lessonProgress = await db.lessonProgress.findMany({
-    where: { userId: user.id, deletedAt: null },
-    select: { lessonId: true, status: true },
-  });
+  // Get user's lesson progress (optimized: scope query to published lessons only to avoid loading full history)
+  const allPublishedLessonIds = courses.flatMap((c) =>
+    c.modules.flatMap((m) => m.lessons.map((l) => l.id))
+  );
+
+  const lessonProgress = allPublishedLessonIds.length > 0
+    ? await db.lessonProgress.findMany({
+        where: { userId: user.id, lessonId: { in: allPublishedLessonIds }, deletedAt: null },
+        select: { lessonId: true, status: true },
+      })
+    : [];
   const progressMap = new Map(lessonProgress.map((p) => [p.lessonId, p.status]));
 
   // Compute aggregate stats