diff --git a/README.md b/README.md
index 7b6a444..76626a5 100644
--- a/README.md
+++ b/README.md
@@ -49,7 +49,9 @@ remindctl list Projects --create
 
 remindctl add "Buy milk"
 remindctl add --title "Call mom" --list Personal --due tomorrow
+remindctl add "Follow up" --parent 4A83
 remindctl edit 1 --title "New title" --due 2026-01-04
+remindctl edit 2 --parent 4A83
 remindctl complete 1 2 3
 remindctl delete 4A83 --force
 remindctl status                # permission status
@@ -68,6 +70,11 @@ Accepted by `--due` and filters:
 - `YYYY-MM-DD HH:mm`
 - ISO 8601 (`2026-01-03T12:34:56Z`)
 
+## Subtasks
+Use `--parent` (or `--under`) with `add` and `edit` to attach a reminder to an existing one. If the underlying
+EventKit API exposes parent relationships on your system, remindctl will set a real subtask. Otherwise it stores
+fallback metadata in the reminder notes as `remindctl-parent: <id>` so the link is preserved.
+
 ## Permissions
 Run `remindctl authorize` to trigger the system prompt. If access is denied, enable
 Terminal (or remindctl) in System Settings → Privacy & Security → Reminders.
diff --git a/REVIEW_NOTES.md b/REVIEW_NOTES.md
new file mode 100644
index 0000000..98b1ced
--- /dev/null
+++ b/REVIEW_NOTES.md
@@ -0,0 +1,10 @@
+# Review notes: subtasks support
+
+- Added `--parent`/`--under` options to `remindctl add` and `remindctl edit` to attach or re-parent reminders.
+- Reminders are validated to stay in the same list as their parent; `edit` will auto-move lists if needed.
+- EventKit parent support is attempted via dynamic selectors (`setParent:` / `setParentReminder:`). If unavailable, remindctl stores fallback metadata in notes (`remindctl-parent: <id>`).
+- Added help/usage examples plus README and manual test updates; new test checks that help includes the parent options.
+
+Things to review:
+- Confirm the dynamic parent selector names are correct for any EventKit version that supports subtasks.
+- Verify the fallback notes behavior is acceptable for your workflow.
diff --git a/Sources/RemindCore/EventKitStore.swift b/Sources/RemindCore/EventKitStore.swift
index e44dc89..a075380 100644
--- a/Sources/RemindCore/EventKitStore.swift
+++ b/Sources/RemindCore/EventKitStore.swift
@@ -103,18 +103,15 @@ public actor RemindersStore {
     if let dueDate = draft.dueDate {
       reminder.dueDateComponents = calendarComponents(from: dueDate)
     }
+    if let parentID = draft.parentID {
+      let parent = try reminder(withID: parentID)
+      try validateParent(parent, matches: calendar)
+      if !applyParent(parent, to: reminder) {
+        reminder.notes = updateParentNotes(current: reminder.notes, parentID: parentID)
+      }
+    }
     try eventStore.save(reminder, commit: true)
-    return ReminderItem(
-      id: reminder.calendarItemIdentifier,
-      title: reminder.title ?? "",
-      notes: reminder.notes,
-      isCompleted: reminder.isCompleted,
-      completionDate: reminder.completionDate,
-      priority: ReminderPriority(eventKitValue: Int(reminder.priority)),
-      dueDate: date(from: reminder.dueDateComponents),
-      listID: reminder.calendar.calendarIdentifier,
-      listName: reminder.calendar.title
-    )
+    return item(from: reminder)
   }
 
   public func updateReminder(id: String, update: ReminderUpdate) async throws -> ReminderItem {
@@ -142,20 +139,17 @@ public actor RemindersStore {
     if let isCompleted = update.isCompleted {
       reminder.isCompleted = isCompleted
     }
+    if let parentID = update.parentID {
+      let parent = try reminder(withID: parentID)
+      try validateParent(parent, matches: reminder.calendar)
+      if !applyParent(parent, to: reminder) {
+        reminder.notes = updateParentNotes(current: reminder.notes, parentID: parentID)
+      }
+    }
 
     try eventStore.save(reminder, commit: true)
 
-    return ReminderItem(
-      id: reminder.calendarItemIdentifier,
-      title: reminder.title ?? "",
-      notes: reminder.notes,
-      isCompleted: reminder.isCompleted,
-      completionDate: reminder.completionDate,
-      priority: ReminderPriority(eventKitValue: Int(reminder.priority)),
-      dueDate: date(from: reminder.dueDateComponents),
-      listID: reminder.calendar.calendarIdentifier,
-      listName: reminder.calendar.title
-    )
+    return item(from: reminder)
   }
 
   public func completeReminders(ids: [String]) async throws -> [ReminderItem] {
@@ -288,4 +282,39 @@ public actor RemindersStore {
       listName: reminder.calendar.title
     )
   }
+
+  private func validateParent(_ parent: EKReminder, matches calendar: EKCalendar) throws {
+    if parent.calendar.calendarIdentifier != calendar.calendarIdentifier {
+      throw RemindCoreError.operationFailed(
+        "Parent reminder is in list \"\(parent.calendar.title)\". Subtasks must be in the same list."
+      )
+    }
+  }
+
+  private func applyParent(_ parent: EKReminder, to reminder: EKReminder) -> Bool {
+    if reminder.responds(to: Selector(("setParent:"))) {
+      _ = reminder.perform(Selector(("setParent:")), with: parent)
+      return true
+    }
+    if reminder.responds(to: Selector(("setParentReminder:"))) {
+      _ = reminder.perform(Selector(("setParentReminder:")), with: parent)
+      return true
+    }
+    return false
+  }
+
+  private func updateParentNotes(current: String?, parentID: String) -> String {
+    let parentLine = "remindctl-parent: \(parentID)"
+    let existing = current?.components(separatedBy: .newlines) ?? []
+    if existing.isEmpty || (existing.count == 1 && existing[0].isEmpty) {
+      return parentLine
+    }
+    var updated = existing
+    if let index = existing.firstIndex(where: { $0.hasPrefix("remindctl-parent: ") }) {
+      updated[index] = parentLine
+    } else {
+      updated.append(parentLine)
+    }
+    return updated.joined(separator: "\n")
+  }
 }
diff --git a/Sources/RemindCore/Models.swift b/Sources/RemindCore/Models.swift
index 5f4fe90..46a699b 100644
--- a/Sources/RemindCore/Models.swift
+++ b/Sources/RemindCore/Models.swift
@@ -82,12 +82,20 @@ public struct ReminderDraft: Sendable {
   public let notes: String?
   public let dueDate: Date?
   public let priority: ReminderPriority
+  public let parentID: String?
 
-  public init(title: String, notes: String?, dueDate: Date?, priority: ReminderPriority) {
+  public init(
+    title: String,
+    notes: String?,
+    dueDate: Date?,
+    priority: ReminderPriority,
+    parentID: String? = nil
+  ) {
     self.title = title
     self.notes = notes
     self.dueDate = dueDate
     self.priority = priority
+    self.parentID = parentID
   }
 }
 
@@ -98,6 +106,7 @@ public struct ReminderUpdate: Sendable {
   public let priority: ReminderPriority?
   public let listName: String?
   public let isCompleted: Bool?
+  public let parentID: String?
 
   public init(
     title: String? = nil,
@@ -105,7 +114,8 @@ public struct ReminderUpdate: Sendable {
     dueDate: Date?? = nil,
     priority: ReminderPriority? = nil,
     listName: String? = nil,
-    isCompleted: Bool? = nil
+    isCompleted: Bool? = nil,
+    parentID: String? = nil
   ) {
     self.title = title
     self.notes = notes
@@ -113,5 +123,6 @@ public struct ReminderUpdate: Sendable {
     self.priority = priority
     self.listName = listName
     self.isCompleted = isCompleted
+    self.parentID = parentID
   }
 }
diff --git a/Sources/remindctl/Commands/AddCommand.swift b/Sources/remindctl/Commands/AddCommand.swift
index 571bc25..e31c61a 100644
--- a/Sources/remindctl/Commands/AddCommand.swift
+++ b/Sources/remindctl/Commands/AddCommand.swift
@@ -16,6 +16,12 @@ enum AddCommand {
           options: [
             .make(label: "title", names: [.long("title")], help: "Reminder title", parsing: .singleValue),
             .make(label: "list", names: [.short("l"), .long("list")], help: "List name", parsing: .singleValue),
+            .make(
+              label: "parent",
+              names: [.long("parent"), .aliasLong("under")],
+              help: "Parent reminder (index or ID prefix)",
+              parsing: .singleValue
+            ),
             .make(label: "due", names: [.short("d"), .long("due")], help: "Due date", parsing: .singleValue),
             .make(label: "notes", names: [.short("n"), .long("notes")], help: "Notes", parsing: .singleValue),
             .make(
@@ -31,6 +37,7 @@ enum AddCommand {
         "remindctl add \"Buy milk\"",
         "remindctl add --title \"Call mom\" --list Personal --due tomorrow",
         "remindctl add \"Review docs\" --priority high",
+        "remindctl add \"Follow up\" --parent 4A83",
       ]
     ) { values, runtime in
       let titleOption = values.option("title")
@@ -53,6 +60,7 @@ enum AddCommand {
       }
 
       let listName = values.option("list")
+      let parentInput = values.option("parent")
       let notes = values.option("notes")
       let dueValue = values.option("due")
       let priorityValue = values.option("priority")
@@ -63,8 +71,22 @@ enum AddCommand {
       let store = RemindersStore()
       try await store.requestAccess()
 
+      var parentReminder: ReminderItem?
+      if let parentInput {
+        let reminders = try await store.reminders(in: nil)
+        let resolved = try IDResolver.resolve([parentInput], from: reminders)
+        parentReminder = resolved.first
+      }
+
       let targetList: String?
-      if let listName {
+      if let parentReminder {
+        if let listName, listName != parentReminder.listName {
+          throw RemindCoreError.operationFailed(
+            "Parent reminder is in list \"\(parentReminder.listName)\". Use that list or omit --list."
+          )
+        }
+        targetList = parentReminder.listName
+      } else if let listName {
         targetList = listName
       } else {
         targetList = await store.defaultListName()
@@ -73,7 +95,13 @@ enum AddCommand {
         throw RemindCoreError.operationFailed("No default list found. Specify --list.")
       }
 
-      let draft = ReminderDraft(title: title, notes: notes, dueDate: dueDate, priority: priority)
+      let draft = ReminderDraft(
+        title: title,
+        notes: notes,
+        dueDate: dueDate,
+        priority: priority,
+        parentID: parentReminder?.id
+      )
       let reminder = try await store.createReminder(draft, listName: targetList)
       OutputRenderer.printReminder(reminder, format: runtime.outputFormat)
     }
diff --git a/Sources/remindctl/Commands/EditCommand.swift b/Sources/remindctl/Commands/EditCommand.swift
index 75a3c31..7123d3a 100644
--- a/Sources/remindctl/Commands/EditCommand.swift
+++ b/Sources/remindctl/Commands/EditCommand.swift
@@ -16,6 +16,12 @@ enum EditCommand {
           options: [
             .make(label: "title", names: [.short("t"), .long("title")], help: "New title", parsing: .singleValue),
             .make(label: "list", names: [.short("l"), .long("list")], help: "Move to list", parsing: .singleValue),
+            .make(
+              label: "parent",
+              names: [.long("parent"), .aliasLong("under")],
+              help: "Set parent reminder (index or ID prefix)",
+              parsing: .singleValue
+            ),
             .make(label: "due", names: [.short("d"), .long("due")], help: "Set due date", parsing: .singleValue),
             .make(label: "notes", names: [.short("n"), .long("notes")], help: "Set notes", parsing: .singleValue),
             .make(
@@ -37,6 +43,7 @@ enum EditCommand {
         "remindctl edit 4A83 --due tomorrow",
         "remindctl edit 2 --priority high --notes \"Call before noon\"",
         "remindctl edit 3 --clear-due",
+        "remindctl edit 2 --parent 4A83",
       ]
     ) { values, runtime in
       guard let input = values.argument(0) else {
@@ -52,8 +59,9 @@ enum EditCommand {
       }
 
       let title = values.option("title")
-      let listName = values.option("list")
+      var listName = values.option("list")
       let notes = values.option("notes")
+      let parentInput = values.option("parent")
 
       var dueUpdate: Date??
       if let dueValue = values.option("due") {
@@ -78,7 +86,31 @@ enum EditCommand {
       }
       let isCompleted: Bool? = completeFlag ? true : (incompleteFlag ? false : nil)
 
-      if title == nil && listName == nil && notes == nil && dueUpdate == nil && priority == nil && isCompleted == nil {
+      var parentReminder: ReminderItem?
+      if let parentInput {
+        let resolvedParent = try IDResolver.resolve([parentInput], from: reminders)
+        parentReminder = resolvedParent.first
+        if parentReminder?.id == reminder.id {
+          throw RemindCoreError.operationFailed("Parent reminder cannot be the reminder being edited")
+        }
+        if let parentReminder, let listName, listName != parentReminder.listName {
+          throw RemindCoreError.operationFailed(
+            "Parent reminder is in list \"\(parentReminder.listName)\". Use that list or omit --list."
+          )
+        }
+        if let parentReminder, listName == nil, reminder.listName != parentReminder.listName {
+          listName = parentReminder.listName
+        }
+      }
+
+      if title == nil
+        && listName == nil
+        && notes == nil
+        && dueUpdate == nil
+        && priority == nil
+        && isCompleted == nil
+        && parentReminder == nil
+      {
         throw RemindCoreError.operationFailed("No changes specified")
       }
 
@@ -88,7 +120,8 @@ enum EditCommand {
         dueDate: dueUpdate,
         priority: priority,
         listName: listName,
-        isCompleted: isCompleted
+        isCompleted: isCompleted,
+        parentID: parentReminder?.id
       )
 
       let updated = try await store.updateReminder(id: reminder.id, update: update)
diff --git a/Tests/remindctlTests/SubtaskHelpTests.swift b/Tests/remindctlTests/SubtaskHelpTests.swift
new file mode 100644
index 0000000..762e7a9
--- /dev/null
+++ b/Tests/remindctlTests/SubtaskHelpTests.swift
@@ -0,0 +1,17 @@
+import Testing
+
+@testable import remindctl
+
+@MainActor
+struct SubtaskHelpTests {
+  @Test("Add/edit help includes parent options")
+  func helpIncludesParent() {
+    let addHelp = HelpPrinter.renderCommand(rootName: "remindctl", spec: AddCommand.spec).joined(separator: "\n")
+    #expect(addHelp.contains("--parent"))
+    #expect(addHelp.contains("--under"))
+
+    let editHelp = HelpPrinter.renderCommand(rootName: "remindctl", spec: EditCommand.spec).joined(separator: "\n")
+    #expect(editHelp.contains("--parent"))
+    #expect(editHelp.contains("--under"))
+  }
+}
diff --git a/docs/manual-tests.md b/docs/manual-tests.md
index 45499ef..f03b7b8 100644
--- a/docs/manual-tests.md
+++ b/docs/manual-tests.md
@@ -16,8 +16,10 @@ Run on a local GUI session (not SSH-only) so the Reminders permission prompt can
 - list lists: `remindctl list`
 - list list contents: `remindctl list "remindctl-manual-YYYYMMDD"`
 - add reminders (3 variants)
+- add subtask: `remindctl add "Follow up" --parent 1`
 - show filters: `today`, `tomorrow`, `week`, `overdue`, `upcoming`, `completed`, `all`
 - edit: update title/notes/priority/due date
+- edit: re-parent reminder with `--parent`
 - complete: mark one reminder complete
 - delete: remove reminders, then delete list