diff --git a/scripts/grade-11.sh b/scripts/grade-11.sh
new file mode 100755
index 0000000..8666182
--- /dev/null
+++ b/scripts/grade-11.sh
@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+
+set -e
+set -uo pipefail
+IFS=$'\n\t'
+
+# Imports library.
+BASEDIR=$(dirname "$0")
+source $BASEDIR/grade-utils.sh
+
+RUNNERS=(
+    "cargo"
+    "cargo --release"
+    "cargo_asan"
+    "cargo_asan --release"
+    "cargo_tsan"
+    "cargo_tsan --release"
+)
+
+# Lints.
+run_linters || exit 1
+
+# Executes test for each runner.
+for RUNNER in "${RUNNERS[@]}"; do
+    echo "Running with $RUNNER..."
+
+    TESTS=("--lib assignment11_grade")
+    if [ $(run_tests) -ne 0 ]; then
+        exit 1
+    fi
+done
+
+exit 0
diff --git a/scripts/prepare-submissions.sh b/scripts/prepare-submissions.sh
index 3a8e550..35ee7ac 100755
--- a/scripts/prepare-submissions.sh
+++ b/scripts/prepare-submissions.sh
@@ -7,3 +7,4 @@ BASEDIR=$(dirname "$0")/..
 mkdir -p $BASEDIR/target
 
 zip -rj $BASEDIR/target/assignment04.zip src/assignments/assignment04
+zip -rj $BASEDIR/target/assignment11.zip src/assignments/assignment11
diff --git a/src/assignments/assignment11/linked_list.rs b/src/assignments/assignment11/linked_list.rs
new file mode 100644
index 0000000..5d772e3
--- /dev/null
+++ b/src/assignments/assignment11/linked_list.rs
@@ -0,0 +1,62 @@
+//! Singly linked list.
+//!
+//! Consult <https://doc.rust-lang.org/book/ch15-01-box.html>.
+
+use std::fmt::Debug;
+
+/// Node of the list.
+#[derive(Debug)]
+pub struct Node<T: Debug> {
+    /// Value of current node.
+    pub value: T,
+
+    /// Pointer to the next node. If it is `None`, there is no next node.
+    pub next: Option<Box<Node<T>>>,
+}
+
+impl<T: Debug> Node<T> {
+    /// Creates a new node.
+    pub fn new(value: T) -> Self {
+        Self { value, next: None }
+    }
+}
+
+/// A singly-linked list.
+#[derive(Debug)]
+pub struct SinglyLinkedList<T: Debug> {
+    /// Head node of the list. If it is `None`, the list is empty.
+    head: Option<Node<T>>,
+}
+
+impl<T: Debug> Default for SinglyLinkedList<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T: Debug> SinglyLinkedList<T> {
+    /// Creates a new list.
+    pub fn new() -> Self {
+        Self { head: None }
+    }
+
+    /// Adds the given node to the front of the list.
+    pub fn push_front(&mut self, value: T) {
+        todo!()
+    }
+
+    /// Adds the given node to the back of the list.
+    pub fn push_back(&mut self, value: T) {
+        todo!()
+    }
+
+    /// Removes and returns the node at the front of the list.
+    pub fn pop_front(&mut self) -> Option<T> {
+        todo!()
+    }
+
+    /// Removes and returns the node at the back of the list.
+    pub fn pop_back(&mut self) -> Option<T> {
+        todo!()
+    }
+}
diff --git a/src/assignments/assignment11/mock_storage.rs b/src/assignments/assignment11/mock_storage.rs
new file mode 100644
index 0000000..a5d9604
--- /dev/null
+++ b/src/assignments/assignment11/mock_storage.rs
@@ -0,0 +1,97 @@
+//! Mock storage.
+//!
+//! Consult <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html#a-use-case-for-interior-mutability-mock-objects>.
+
+use std::cell::RefCell;
+use std::collections::HashMap;
+
+/// Mock storage.
+#[derive(Debug)]
+pub struct MockStorage {
+    /// Files stored in the storage.
+    ///
+    /// Each entry of the hashmap represents the `(name, size)` of the file.
+    files: RefCell<HashMap<String, usize>>,
+
+    /// Capacity of the storage.
+    ///
+    /// The total size of files stored on the storage cannot exceed the capacity.
+    capacity: usize,
+}
+
+impl MockStorage {
+    /// Creates a new mock storage.
+    pub fn new(capacity: usize) -> Self {
+        Self {
+            files: RefCell::new(HashMap::new()),
+            capacity,
+        }
+    }
+}
+
+/// Trait for storage object.
+pub trait Storage {
+    /// Uploads a file. If a file with the same name already exists in the storage, overwrite it.
+    ///
+    /// Returns `Err` with insufficient memory size if there is no free space to upload a file.
+    fn upload(&self, name: &str, size: usize) -> Result<(), usize>;
+
+    /// Returns the used memory size of the storage.
+    fn used(&self) -> usize;
+
+    /// Returns the capacity of the storage.
+    fn capacity(&self) -> usize;
+}
+
+impl Storage for MockStorage {
+    fn upload(&self, name: &str, size: usize) -> Result<(), usize> {
+        todo!()
+    }
+
+    fn used(&self) -> usize {
+        todo!()
+    }
+
+    fn capacity(&self) -> usize {
+        todo!()
+    }
+}
+
+/// File uploader.
+///
+/// It uploads files to the internal storage.
+#[derive(Debug)]
+pub struct FileUploader<'a, T: Storage> {
+    storage: &'a T,
+}
+
+impl<'a, T: Storage> FileUploader<'a, T> {
+    /// Creates a new file uploader with given internal storage.
+    pub fn new(storage: &'a T) -> Self {
+        Self { storage }
+    }
+
+    /// Uploads a file to the internal storage.
+    pub fn upload(&self, name: &str, size: usize) -> Result<(), usize> {
+        todo!()
+    }
+}
+
+/// Storage usage analyzer.
+#[derive(Debug)]
+pub struct UsageAnalyzer<'a, T: Storage> {
+    storage: &'a T,
+    bound: f64,
+}
+
+impl<'a, T: Storage> UsageAnalyzer<'a, T> {
+    /// Creates a new usage analyzer.
+    pub fn new(storage: &'a T, bound: f64) -> Self {
+        Self { storage, bound }
+    }
+
+    /// Returns `true` if the usage of the internal storage is under the bound.
+    pub fn is_usage_under_bound(&self) -> bool {
+        todo!()
+    }
+}
diff --git a/src/assignments/assignment11/mod.rs b/src/assignments/assignment11/mod.rs
new file mode 100644
index 0000000..64b4553
--- /dev/null
+++ b/src/assignments/assignment11/mod.rs
@@ -0,0 +1,9 @@
+//! Assignment 11: Familiarizing with smart pointers.
+//!
+//! You should fill out `todo!()` placeholders in such a way that `/scripts/grade-11.sh` works fine.
+//! See `assignment11_grade.rs` and `/scripts/grade-11.sh` for the test script.
+//! Run `/scripts/prepare-submissions.sh` and submit `/target/assignment11.zip` to <https://gg.kaist.ac.kr>.
+
+pub mod linked_list;
+pub mod mock_storage;
+pub mod tv_room;
diff --git a/src/assignments/assignment11/tv_room.rs b/src/assignments/assignment11/tv_room.rs
new file mode 100644
index 0000000..0315341
--- /dev/null
+++ b/src/assignments/assignment11/tv_room.rs
@@ -0,0 +1,108 @@
+//! TV Room Simulator.
+//!
+//! People can come to the TV room and watch TV. There are two types of TV watchers, manager and guest.
+//!
+//! The rule of the TV room is as follows:
+//!
+//! - Closed TV room can be opened by the manager.
+//! - Guests can enter the TV room by the manager.
+//! - Manager can leave the TV room earlier than guests.
+//! - The TV room closes when the last person left the TV room.
+//!
+//! Both `Manager` and `Guest` have 'Rc<Watcher>' as a field, and its reference count indicates the number of people in
+//! the TV room. When the 'Manager' and 'Guest' object is dropped, it means that the person leaves the TV room.
+//!
+//! Consult the following documentations:
+//! - <https://doc.rust-lang.org/book/ch15-04-rc.html#rct-the-reference-counted-smart-pointer>
+//! - <https://doc.rust-lang.org/book/ch15-05-interior-mutability.html#having-multiple-owners-of-mutable-data-by-combining-rct-and-refcellt>
+
+use std::{cell::RefCell, rc::Rc};
+
+#[derive(Debug, Clone, Copy)]
+enum TVRoomState {
+    Opened,
+    Closed,
+}
+
+/// TV Room
+#[derive(Debug)]
+pub struct TVRoom {
+    /// Indicates whether the TV room is state.
+    state: RefCell<TVRoomState>,
+}
+
+impl Default for TVRoom {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl TVRoom {
+    /// Creates a new TV room.
+    ///
+    /// Initial state of the TV room is closed.
+    pub fn new() -> Self {
+        Self {
+            state: RefCell::new(TVRoomState::Closed),
+        }
+    }
+
+    /// Opens the TV room and returns the manager.
+    ///
+    /// Returns `None` if the TV room is already opened.
+    pub fn open(&self) -> Option<Manager<'_>> {
+        todo!()
+    }
+
+    /// Returns whether the TV room is opened or not.
+    pub fn is_opened(&self) -> bool {
+        todo!()
+    }
+}
+
+/// TV Room Manager.
+///
+/// - The manager is special TV's watcher that has privileges to add other guests.
+/// - If all watchers including the manager drop (~= leave the TV room), the TV must be turned off.
+/// - Note that the manager can be dropped while other watchers are watching TV.
+#[derive(Debug)]
+pub struct Manager<'a> {
+    inner: Rc<Watcher<'a>>,
+}
+
+impl<'a> Manager<'a> {
+    fn new(tvstate: &'a RefCell<TVRoomState>) -> Self {
+        Self {
+            inner: Rc::new(Watcher::new(tvstate)),
+        }
+    }
+
+    /// Adds new guest to the TV room.
+    pub fn new_guest(&self) -> Guest<'a> {
+        todo!()
+    }
+}
+
+/// TV Room Guest.
+#[derive(Debug)]
+pub struct Guest<'a> {
+    inner: Rc<Watcher<'a>>,
+}
+
+#[derive(Debug)]
+struct Watcher<'a> {
+    tvstate: &'a RefCell<TVRoomState>,
+}
+
+impl<'a> Watcher<'a> {
+    fn new(tvstate: &'a RefCell<TVRoomState>) -> Self {
+        Self { tvstate }
+    }
+}
+
+impl Drop for Watcher<'_> {
+    fn drop(&mut self) {
+        // When the last person leaves the TV room, the TV room should be closed.
+        todo!()
+    }
+}
diff --git a/src/assignments/assignment11_grade.rs b/src/assignments/assignment11_grade.rs
new file mode 100644
index 0000000..94d2902
--- /dev/null
+++ b/src/assignments/assignment11_grade.rs
@@ -0,0 +1,81 @@
+#[cfg(test)]
+mod test {
+
+    #[test]
+    fn test_tv_room() {
+        use crate::assignments::assignment11::tv_room::*;
+
+        let tv_room = TVRoom::new();
+        assert!(!tv_room.is_opened());
+
+        // Turn on and add new guests.
+        let manager = tv_room.open().unwrap();
+        assert!(tv_room.is_opened());
+        let guest1 = manager.new_guest();
+        let guest2 = manager.new_guest();
+        drop(manager);
+        drop(guest1);
+        assert!(tv_room.open().is_none());
+        drop(guest2);
+        assert!(!tv_room.is_opened());
+
+        // Turn on and add new guests.
+        let manager = tv_room.open().unwrap();
+        assert!(tv_room.is_opened());
+        let guest3 = manager.new_guest();
+        drop(guest3);
+        assert!(tv_room.is_opened());
+        drop(manager);
+        assert!(!tv_room.is_opened());
+    }
+
+    #[test]
+    fn test_mock_storage() {
+        use crate::assignments::assignment11::mock_storage::*;
+
+        let mock_storage = MockStorage::new(100);
+
+        let uploader1 = FileUploader::new(&mock_storage);
+        let uploader2 = FileUploader::new(&mock_storage);
+
+        let usage_analyzer = UsageAnalyzer::new(&mock_storage, 0.75);
+
+        assert!(uploader1.upload("file1.txt", 20).is_ok());
+        assert!(usage_analyzer.is_usage_under_bound());
+
+        assert!(uploader2.upload("file2.txt", 30).is_ok());
+        assert!(usage_analyzer.is_usage_under_bound());
+
+        assert!(uploader1.upload("file3.txt", 40).is_ok());
+        assert!(!usage_analyzer.is_usage_under_bound());
+
+        assert_eq!(uploader2.upload("file4.txt", 50), Err(40));
+        assert!(!usage_analyzer.is_usage_under_bound());
+
+        assert!(uploader1.upload("file3.txt", 10).is_ok());
+        assert!(usage_analyzer.is_usage_under_bound());
+    }
+
+    #[derive(Debug, PartialEq, Eq)]
+    struct V(usize);
+
+    #[test]
+    fn test_linked_list() {
+        use crate::assignments::assignment11::linked_list::*;
+
+        let mut list = SinglyLinkedList::new();
+        list.push_back(V(3));
+        list.push_front(V(2));
+        list.push_back(V(4));
+        list.push_front(V(1));
+        list.push_back(V(5));
+
+        assert_eq!(list.pop_front(), Some(V(1)));
+        assert_eq!(list.pop_back(), Some(V(5)));
+        assert_eq!(list.pop_front(), Some(V(2)));
+        assert_eq!(list.pop_back(), Some(V(4)));
+        assert_eq!(list.pop_front(), Some(V(3)));
+        assert_eq!(list.pop_back(), None);
+        assert_eq!(list.pop_front(), None);
+    }
+}
diff --git a/src/assignments/mod.rs b/src/assignments/mod.rs
index a616d50..b69cbdb 100644
--- a/src/assignments/mod.rs
+++ b/src/assignments/mod.rs
@@ -24,3 +24,5 @@ pub mod assignment09;
 mod assignment09_grade;
 pub mod assignment10;
 mod assignment10_grade;
+pub mod assignment11;
+mod assignment11_grade;