diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 7ede98ae..5bd8c871 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -22,7 +22,9 @@ jobs:
           - '3.11'
           - '3.12'
           - '3.13'
-          - '3.14.0-rc.2'
+          - '3.13t'
+          - '3.14'
+          - '3.14t'
         arch:
           - 'arm64'
           - 'x86'
@@ -77,9 +79,10 @@ jobs:
         with:
           python-version: ${{ matrix.py }}
           architecture: ${{ matrix.arch }}
+          allow-prereleases: true
 
       - name: Install Rust
-        if: matrix.arch != 'x86' && matrix.py != '3.14.0-rc.2'
+        if: matrix.arch != 'x86' && (matrix.py != '3.14' || matrix.py != '3.14t') 
         uses: dtolnay/rust-toolchain@b3b07ba8b418998c39fb20f53e8b695cdcc8de1b # v1
         with:
           toolchain: stable
@@ -96,14 +99,14 @@ jobs:
           python -m pip install --require-hashes -r ci/requirements.txt
 
       - name: Build (Rust)
-        if: matrix.arch != 'x86' && matrix.py != '3.14.0-rc.2'
+        if: matrix.arch != 'x86' && (matrix.py != '3.14' || matrix.py != '3.14t') 
         env:
           PIP_CONSTRAINT: 'ci/constraints.txt'
         run: |
           python -m pip -v install --config-settings='--build-option=--rust-backend' -e .
 
       - name: Build (No Rust)
-        if: matrix.arch == 'x86' || matrix.py == '3.14.0-rc.2'
+        if: matrix.arch == 'x86' || matrix.py == '3.14' || matrix.py == '3.14t'
         env:
           PIP_CONSTRAINT: 'ci/constraints.txt'
         run: |
@@ -114,13 +117,14 @@ jobs:
           pytest --numprocesses=auto --hypothesis-profile=${HYPOTHESIS_PROFILE} -v tests/
 
       - name: Test CFFI Backend
+        if: matrix.py != '3.13t'
         env:
           PYTHON_ZSTANDARD_IMPORT_POLICY: 'cffi'
         run: |
           pytest --numprocesses=auto --hypothesis-profile=${HYPOTHESIS_PROFILE} -v tests/
 
       - name: Test Rust Backend
-        if: matrix.arch != 'x86' && matrix.py != '3.14.0-rc.2'
+        if: matrix.arch != 'x86' && (matrix.py != '3.14' || matrix.py != '3.14t' )
         # Rust backend is currently experimental. So ignore failures in it.
         continue-on-error: true
         env:
diff --git a/.github/workflows/typing.yml b/.github/workflows/typing.yml
index 4ad483ac..7d56e7d0 100644
--- a/.github/workflows/typing.yml
+++ b/.github/workflows/typing.yml
@@ -15,7 +15,9 @@ jobs:
           - '3.11'
           - '3.12'
           - '3.13'
+          - '3.13t'
           - '3.14'
+          - '3.14t'
     runs-on: 'ubuntu-24.04'
     steps:
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
diff --git a/.github/workflows/wheel.yml b/.github/workflows/wheel.yml
index c993e5c8..d8af256e 100644
--- a/.github/workflows/wheel.yml
+++ b/.github/workflows/wheel.yml
@@ -29,7 +29,9 @@ jobs:
           - 'cp311-cp311'
           - 'cp312-cp312'
           - 'cp313-cp313'
+          - 'cp313-cp313t'
           - 'cp314-cp314'
+          - 'cp314-cp314t'
         exclude:
           - image: 'musllinux_1_1_aarch64'
             py: 'cp314-cp314'
@@ -65,7 +67,9 @@ jobs:
           - 'cp311'
           - 'cp312'
           - 'cp313'
+          - 'cp313t'
           - 'cp314'
+          - 'cp314t'
         arch:
           - 'arm64'
           - 'x86_64'
@@ -74,7 +78,9 @@ jobs:
       CIBW_ARCHS: ${{ matrix.arch }}
       CIBW_BUILD: ${{ matrix.py }}-*
       CIBW_BUILD_VERBOSITY: '1'
+      CIBW_ENABLE: cpython-prerelease cpython-freethreading
       ZSTD_WARNINGS_AS_ERRORS: '1'
+
     steps:
       - name: Set up Python
         uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
@@ -109,7 +115,9 @@ jobs:
           - '3.11'
           - '3.12'
           - '3.13'
-          - '3.14.0-rc.2'
+          - '3.13t'
+          - '3.14'
+          - '3.14t'
         arch:
           - 'x86'
           - 'x64'
@@ -130,6 +138,7 @@ jobs:
         with:
           python-version: ${{ matrix.py }}
           architecture: ${{ matrix.arch }}
+          allow-prereleases: true
 
       - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
         with:
diff --git a/Cargo.lock b/Cargo.lock
index 73ce919d..15fa1e5c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -250,11 +250,10 @@ dependencies = [
 
 [[package]]
 name = "pyo3"
-version = "0.24.2"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e5203598f366b11a02b13aa20cab591229ff0a89fd121a308a5df751d5fc9219"
+checksum = "8970a78afe0628a3e3430376fc5fd76b6b45c4d43360ffd6cdd40bdde72b682a"
 dependencies = [
- "cfg-if",
  "indoc",
  "libc",
  "memoffset",
@@ -268,9 +267,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-build-config"
-version = "0.24.2"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "99636d423fa2ca130fa5acde3059308006d46f98caac629418e53f7ebb1e9999"
+checksum = "458eb0c55e7ece017adeba38f2248ff3ac615e53660d7c71a238d7d2a01c7598"
 dependencies = [
  "once_cell",
  "target-lexicon",
@@ -278,9 +277,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-ffi"
-version = "0.24.2"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "78f9cf92ba9c409279bc3305b5409d90db2d2c22392d443a87df3a1adad59e33"
+checksum = "7114fe5457c61b276ab77c5055f206295b812608083644a5c5b2640c3102565c"
 dependencies = [
  "libc",
  "pyo3-build-config",
@@ -288,9 +287,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros"
-version = "0.24.2"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b999cb1a6ce21f9a6b147dcf1be9ffedf02e0043aec74dc390f3007047cecd9"
+checksum = "a8725c0a622b374d6cb051d11a0983786448f7785336139c3c94f5aa6bef7e50"
 dependencies = [
  "proc-macro2",
  "pyo3-macros-backend",
@@ -300,9 +299,9 @@ dependencies = [
 
 [[package]]
 name = "pyo3-macros-backend"
-version = "0.24.2"
+version = "0.25.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "822ece1c7e1012745607d5cf0bcb2874769f0f7cb34c4cde03b9358eb9ef911a"
+checksum = "4109984c22491085343c05b0dbc54ddc405c3cf7b4374fc533f5c3313a572ccc"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -313,7 +312,7 @@ dependencies = [
 
 [[package]]
 name = "python-zstandard"
-version = "0.24.0-pre"
+version = "0.25.0-pre"
 dependencies = [
  "libc",
  "num_cpus",
diff --git a/Cargo.toml b/Cargo.toml
index ccf3237d..a8f8e0eb 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -26,5 +26,5 @@ version = "2.0.10+zstd.1.5.6"
 features = ["experimental", "legacy", "zstdmt"]
 
 [dependencies.pyo3]
-version = "0.24.2"
+version = "0.25.1"
 features = ["extension-module"]
diff --git a/c-ext/backend_c.c b/c-ext/backend_c.c
index 4b09d1fb..888a6767 100644
--- a/c-ext/backend_c.c
+++ b/c-ext/backend_c.c
@@ -313,7 +313,7 @@ size_t roundpow2(size_t i) {
 int safe_pybytes_resize(PyObject **obj, Py_ssize_t size) {
     PyObject *tmp;
 
-    if ((*obj)->ob_refcnt == 1) {
+    if (Py_REFCNT(*obj) == 1) {
         return _PyBytes_Resize(obj, size);
     }
 
diff --git a/pyproject.toml b/pyproject.toml
index dca8a82a..e91e1281 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,13 +19,17 @@ classifiers = [
     "Programming Language :: Python :: 3.12",
     "Programming Language :: Python :: 3.13",
     "Programming Language :: Python :: 3.14",
+    "Programming Language :: Python :: Free Threading :: 1 - Unstable",
+    "Programming Language :: Python :: Free Threading",
+
 ]
 keywords = ["zstandard", "zstd", "compression"]
 dependencies = []
 
 [project.optional-dependencies]
 cffi = [
-    'cffi>=1.17 ; python_version >= "3.13" and platform_python_implementation != "PyPy"',
+    "cffi~=1.17; platform_python_implementation != 'PyPy' and python_version < '3.14'",
+    "cffi>=2.0.0b; platform_python_implementation != 'PyPy' and python_version >= '3.14'",
 ]
 
 [project.urls]
@@ -34,7 +38,8 @@ Documentation = "https://python-zstandard.readthedocs.io/en/latest/"
 
 [build-system]
 requires = [
-    "cffi>=1.17.0 ; platform_python_implementation != 'PyPy'",
+    "cffi~=1.17; platform_python_implementation != 'PyPy' and python_version < '3.14'",
+    "cffi>=2.0.0b; platform_python_implementation != 'PyPy' and python_version >= '3.14'",
     "packaging",
     "setuptools",
 ]
diff --git a/rust-ext/src/buffers.rs b/rust-ext/src/buffers.rs
index b48b7660..00c1ddd8 100644
--- a/rust-ext/src/buffers.rs
+++ b/rust-ext/src/buffers.rs
@@ -11,7 +11,7 @@ use {
         exceptions::{PyIndexError, PyTypeError, PyValueError},
         ffi::Py_buffer,
         prelude::*,
-        types::{PyBytes, PyTuple},
+        types::{PyBytes, PyTuple}, IntoPyObjectExt,
     },
 };
 
@@ -242,7 +242,7 @@ impl ZstdBufferWithSegments {
         }
 
         Ok(Self {
-            source: data.into_py(py),
+            source: data.into_py_any(py).unwrap(),
             buffer: data_buffer,
             segments,
         })
@@ -344,7 +344,7 @@ impl ZstdBufferWithSegmentsCollection {
 
             offset += segment.segments.len();
 
-            buffers.push(item.to_object(py));
+            buffers.push(item.into_py_any(py).unwrap());
             first_elements.push(offset);
         }
 
diff --git a/rust-ext/src/compression_chunker.rs b/rust-ext/src/compression_chunker.rs
index c3828302..4e8b3276 100644
--- a/rust-ext/src/compression_chunker.rs
+++ b/rust-ext/src/compression_chunker.rs
@@ -10,7 +10,7 @@ use {
         stream::{make_in_buffer_source, InBufferSource},
         zstd_safe::CCtx,
     },
-    pyo3::{prelude::*, types::PyBytes},
+    pyo3::{prelude::*, types::PyBytes, IntoPyObjectExt},
     std::sync::Arc,
 };
 
@@ -225,7 +225,7 @@ impl ZstdCompressionChunkerIterator {
                 let chunk = PyBytes::new(py, &slf.dest_buffer);
                 slf.dest_buffer.clear();
 
-                return Ok(Some(chunk.into_py(py)));
+                return Ok(Some(chunk.into_py_any(py).unwrap()));
             }
 
             // Else continue to compress available input data.
@@ -278,6 +278,6 @@ impl ZstdCompressionChunkerIterator {
         let chunk = PyBytes::new(py, &slf.dest_buffer);
         slf.dest_buffer.clear();
 
-        Ok(Some(chunk.into_py(py)))
+        Ok(Some(chunk.into_py_any(py).unwrap()))
     }
 }
diff --git a/rust-ext/src/compression_writer.rs b/rust-ext/src/compression_writer.rs
index 570c24ea..b7f12366 100644
--- a/rust-ext/src/compression_writer.rs
+++ b/rust-ext/src/compression_writer.rs
@@ -10,7 +10,7 @@ use {
         buffer::PyBuffer,
         exceptions::{PyNotImplementedError, PyOSError, PyValueError},
         prelude::*,
-        types::PyBytes,
+        types::PyBytes, IntoPyObjectExt,
     },
     std::sync::Arc,
 };
@@ -48,7 +48,7 @@ impl ZstdCompressionWriter {
 
         Ok(Self {
             cctx,
-            writer: writer.into_py(py),
+            writer: writer.into_py_any(py).unwrap(),
             write_return_read,
             closefd,
             entered: false,
diff --git a/rust-ext/src/compressor_iterator.rs b/rust-ext/src/compressor_iterator.rs
index 7810594a..a8223c91 100644
--- a/rust-ext/src/compressor_iterator.rs
+++ b/rust-ext/src/compressor_iterator.rs
@@ -10,7 +10,7 @@ use {
         stream::{make_in_buffer_source, InBufferSource},
         zstd_safe::CCtx,
     },
-    pyo3::{prelude::*, types::PyBytes},
+    pyo3::{prelude::*, types::PyBytes, IntoPyObjectExt},
     std::sync::Arc,
 };
 
@@ -60,7 +60,7 @@ impl ZstdCompressorIterator {
                 // TODO avoid buffer copy
                 let chunk = PyBytes::new(py, &dest_buffer);
 
-                return Ok(Some(chunk.into_py(py)));
+                return Ok(Some(chunk.into_py_any(py).unwrap()));
             }
 
             // Else read another chunk in hopes of producing output data.
@@ -94,7 +94,7 @@ impl ZstdCompressorIterator {
             // TODO avoid buffer copy.
             let chunk = PyBytes::new(py, &dest_buffer);
 
-            return Ok(Some(chunk.into_py(py)));
+            return Ok(Some(chunk.into_py_any(py).unwrap()));
         }
 
         Ok(None)
diff --git a/rust-ext/src/decompression_writer.rs b/rust-ext/src/decompression_writer.rs
index b6321acc..3ae45424 100644
--- a/rust-ext/src/decompression_writer.rs
+++ b/rust-ext/src/decompression_writer.rs
@@ -10,7 +10,7 @@ use {
         buffer::PyBuffer,
         exceptions::{PyOSError, PyValueError},
         prelude::*,
-        types::PyBytes,
+        types::PyBytes, IntoPyObjectExt,
     },
     std::sync::Arc,
 };
@@ -40,7 +40,7 @@ impl ZstdDecompressionWriter {
     ) -> PyResult<Self> {
         Ok(Self {
             dctx,
-            writer: writer.into_py(py),
+            writer: writer.into_py_any(py).unwrap(),
             write_size,
             write_return_read,
             closefd,
diff --git a/rust-ext/src/decompressor_iterator.rs b/rust-ext/src/decompressor_iterator.rs
index ce7d9a8f..38a4f04f 100644
--- a/rust-ext/src/decompressor_iterator.rs
+++ b/rust-ext/src/decompressor_iterator.rs
@@ -10,7 +10,7 @@ use {
         stream::{make_in_buffer_source, InBufferSource},
         zstd_safe::DCtx,
     },
-    pyo3::{exceptions::PyValueError, prelude::*, types::PyBytes},
+    pyo3::{exceptions::PyValueError, prelude::*, types::PyBytes, IntoPyObjectExt},
     std::{cmp::min, sync::Arc},
 };
 
@@ -60,7 +60,7 @@ impl ZstdDecompressorIterator {
             if !dest_buffer.is_empty() {
                 // TODO avoid buffer copy.
                 let chunk = PyBytes::new(py, &dest_buffer);
-                return Ok(Some(chunk.into_py(py)));
+                return Ok(Some(chunk.into_py_any(py).unwrap()));
             }
 
             // Repeat loop to collect more input data.
@@ -71,7 +71,7 @@ impl ZstdDecompressorIterator {
         if !dest_buffer.is_empty() {
             // TODO avoid buffer copy.
             let chunk = PyBytes::new(py, &dest_buffer);
-            Ok(Some(chunk.into_py(py)))
+            Ok(Some(chunk.into_py_any(py).unwrap()))
         } else {
             Ok(None)
         }
diff --git a/rust-ext/src/stream.rs b/rust-ext/src/stream.rs
index 89b35e98..130184e6 100644
--- a/rust-ext/src/stream.rs
+++ b/rust-ext/src/stream.rs
@@ -5,7 +5,7 @@
 // of the BSD license. See the LICENSE file for details.
 
 use {
-    pyo3::{buffer::PyBuffer, exceptions::PyValueError, prelude::*},
+    pyo3::{buffer::PyBuffer, exceptions::PyValueError, prelude::*, IntoPyObjectExt},
     zstd_sys::ZSTD_inBuffer,
 };
 
@@ -139,7 +139,7 @@ pub(crate) fn make_in_buffer_source(
 ) -> PyResult<Box<dyn InBufferSource + Send>> {
     if source.hasattr("read")? {
         Ok(Box::new(ReadSource {
-            source: source.into_py(py),
+            source: source.into_py_any(py).unwrap(),
             buffer: None,
             read_size,
             finished: false,
@@ -153,7 +153,7 @@ pub(crate) fn make_in_buffer_source(
         })?;
 
         Ok(Box::new(BufferSource {
-            source: source.into_py(py),
+            source: source.into_py_any(py).unwrap(),
             buffer,
             offset: 0,
         }))
diff --git a/setup.py b/setup.py
index f868a924..cfd77f97 100755
--- a/setup.py
+++ b/setup.py
@@ -10,6 +10,7 @@
 import os
 import platform
 import sys
+import sysconfig
 
 from setuptools import setup
 
@@ -30,7 +31,8 @@
 # garbage collection pitfalls.
 # Require 1.17 everywhere so we don't have to think about supporting older
 # versions.
-MINIMUM_CFFI_VERSION = "1.17"
+# Require 2.0 for Python 3.14+ to add improved free-threading support
+MINIMUM_CFFI_VERSION = "2.0" if sys.version_info[0:2] >= (3, 14) else "1.17"
 
 ext_suffix = os.environ.get("SETUPTOOLS_EXT_SUFFIX")
 if ext_suffix:
@@ -89,6 +91,10 @@
 if platform.python_implementation() == "PyPy":
     C_BACKEND = False
 
+# cffi 2.0 only introduced no-GIL support for 3.14+.
+if platform.python_implementation() == "CPython" and sys.version_info[0:2] == (3, 13) and sysconfig.get_config_var("Py_GIL_DISABLED"):
+    CFFI_BACKEND = False
+
 if "--legacy" in sys.argv:
     SUPPORT_LEGACY = True
     sys.argv.remove("--legacy")