diff --git a/.github/workflows/build_wheels.yml b/.github/workflows/build_wheels.yml
index 9f14b28..31a74cd 100644
--- a/.github/workflows/build_wheels.yml
+++ b/.github/workflows/build_wheels.yml
@@ -17,14 +17,15 @@ jobs:
         # cibuildwheel builds linux wheels inside a manylinux container
         # it also takes care of procuring the correct python version for us
         os: [ubuntu-latest, windows-latest, macos-latest]
-        python-version: [39, 310, 311, 312, 313]
+        python-version: [39, 310, 311, 312, 313, 313t, 314, 314t]
 
     steps:
       - uses: actions/checkout@v4
 
-      - uses: pypa/cibuildwheel@v2.22.0
+      - uses: pypa/cibuildwheel@v3.1.4
         env:
           CIBW_BUILD: "cp${{ matrix.python-version}}-*"
+          CIBW_ENABLE: cpython-freethreading
 
       - uses: actions/upload-artifact@v4
         with:
@@ -39,19 +40,20 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-24.04-arm]
-        python-version: [39, 310, 311, 312, 313]
+        python-version: [39, 310, 311, 312, 313, 313t, 314, 314t]
 
     steps:
       - uses: actions/checkout@v4
 
       - name: Build wheels
-        uses: pypa/cibuildwheel@v2.22.0
+        uses: pypa/cibuildwheel@v3.1.4
         env:
           CIBW_BUILD: "cp${{ matrix.python-version}}-*"
           CIBW_ARCHS: aarch64
           CIBW_BUILD_VERBOSITY: 3
           # https://github.com/rust-lang/cargo/issues/10583
           CIBW_ENVIRONMENT_LINUX: PATH="$PATH:$HOME/.cargo/bin" CARGO_NET_GIT_FETCH_WITH_CLI=true
+          CIBW_ENABLE: cpython-freethreading
 
       - uses: actions/upload-artifact@v4
         with:
diff --git a/src/lib.rs b/src/lib.rs
index 80f4acc..5e89bfd 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -187,7 +187,7 @@ impl std::error::Error for EncodeError {}
 
 const MAX_NUM_THREADS: usize = 128;
 
-#[cfg_attr(feature = "python", pyclass)]
+#[cfg_attr(feature = "python", pyclass(frozen))]
 #[derive(Clone)]
 pub struct CoreBPE {
     encoder: HashMap<Vec<u8>, Rank>,
diff --git a/src/py.rs b/src/py.rs
index 253e5d0..ee8c52d 100644
--- a/src/py.rs
+++ b/src/py.rs
@@ -183,7 +183,7 @@ impl CoreBPE {
     }
 }
 
-#[pyclass]
+#[pyclass(frozen)]
 struct TiktokenBuffer {
     tokens: Vec<Rank>,
 }
@@ -248,7 +248,7 @@ impl TiktokenBuffer {
     }
 }
 
-#[pymodule]
+#[pymodule(gil_used = false)]
 fn _tiktoken(_py: Python, m: &Bound<PyModule>) -> PyResult<()> {
     m.add_class::<CoreBPE>()?;
     Ok(())