diff --git a/docs/dev-notes/2026-03-01/add-aoj-course-to-contests/plan.md b/docs/dev-notes/2026-03-01/add-aoj-course-to-contests/plan.md
new file mode 100644
index 000000000..7babb2e47
--- /dev/null
+++ b/docs/dev-notes/2026-03-01/add-aoj-course-to-contests/plan.md
@@ -0,0 +1,7 @@
+# AOJ コースへの DSL・CGL・NTL 追加 (Issue #3223)
+
+[Issue #3223](https://github.com/AtCoder-NoviSteps/AtCoderNoviSteps/issues/3223) で、AOJ の DSL (18問)・CGL (25問)・NTL (11問) を追加。`AOJ_COURSES` に3件追記するだけで、アーキテクチャ上の変更は不要。`AOJ_COURSES` を参照する関数はデータ駆動のため変更不要。
+
+## 注意事項
+
+AOJ の `/problems?size=N` は存在しない問題を返すことがある。現在の `id` 生成ロジックは `sha256(contest_id + task.title)` のため、タイトル重複時に `Task.id` 一意制約違反 (P2002) が発生する（CGL で確認）。根本対処は `task.id`（API のユニーク識別子）を使うこと。暫定対処として存在する問題のみインポート。
diff --git a/src/lib/utils/contest.ts b/src/lib/utils/contest.ts
index 9df44b5b1..74319b8e1 100644
--- a/src/lib/utils/contest.ts
+++ b/src/lib/utils/contest.ts
@@ -225,6 +225,9 @@ export const AOJ_COURSES: ContestPrefix = {
   ITP2: 'プログラミング応用',
   DPL: '組み合わせ最適化',
   GRL: 'グラフ',
+  DSL: 'データ構造',
+  CGL: '計算幾何学',
+  NTL: '整数論',
 } as const;
 
 export function getPrefixForAojCourses() {
diff --git a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts b/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
index a07e6da9f..ef9e64046 100644
--- a/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
+++ b/src/test/lib/utils/test_cases/contest_name_and_task_index.ts
@@ -593,6 +593,10 @@ export const agc = generateAgcTestCases(
  * - ALDS1: Algorithms and Data Structures I
  * - ITP2: Introduction to Programming II
  * - DPL: Discrete Optimization Problems
+ * - GRL: Graph Algorithms
+ * - DSL: Data Set and Queries
+ * - CGL: Computational Geometry
+ * - NTL: Number Theory
  */
 const AOJ_COURSES_TEST_DATA = {
   ITP1: {
@@ -615,6 +619,18 @@ const AOJ_COURSES_TEST_DATA = {
     contestId: 'GRL',
     tasks: ['1_A', '1_C', '6_B', '7_A'],
   },
+  DSL: {
+    contestId: 'DSL',
+    tasks: ['1_A', '2_H'],
+  },
+  CGL: {
+    contestId: 'CGL',
+    tasks: ['1_A', '7_I'],
+  },
+  NTL: {
+    contestId: 'NTL',
+    tasks: ['1_A', '2_F'],
+  },
 };
 
 const generateAojCoursesTestCases = (
diff --git a/src/test/lib/utils/test_cases/contest_type.ts b/src/test/lib/utils/test_cases/contest_type.ts
index 5299c13b9..d5b628350 100644
--- a/src/test/lib/utils/test_cases/contest_type.ts
+++ b/src/test/lib/utils/test_cases/contest_type.ts
@@ -508,6 +508,9 @@ const aojCoursesData = [
   { name: 'AOJ Courses, ITP2', contestId: 'ITP2' },
   { name: 'AOJ Courses, DPL', contestId: 'DPL' },
   { name: 'AOJ Courses, GRL', contestId: 'GRL' },
+  { name: 'AOJ Courses, DSL', contestId: 'DSL' },
+  { name: 'AOJ Courses, CGL', contestId: 'CGL' },
+  { name: 'AOJ Courses, NTL', contestId: 'NTL' },
 ];
 
 export const aojCourses = aojCoursesData.map(({ name, contestId }) =>
diff --git a/src/test/lib/utils/test_cases/task_url.ts b/src/test/lib/utils/test_cases/task_url.ts
index a67f2d1c3..2cf596094 100644
--- a/src/test/lib/utils/test_cases/task_url.ts
+++ b/src/test/lib/utils/test_cases/task_url.ts
@@ -104,6 +104,18 @@ const courses = [
     contestId: 'GRL',
     tasks: ['1_A', '1_C', '6_B', '7_A'],
   },
+  {
+    contestId: 'DSL',
+    tasks: ['1_A', '1_B', '2_I', '5_B'],
+  },
+  {
+    contestId: 'CGL',
+    tasks: ['1_A', '1_C', '7_I'],
+  },
+  {
+    contestId: 'NTL',
+    tasks: ['1_A', '1_E', '2_F'],
+  },
 ];
 
 export const aojCourses = courses.flatMap((course) =>