diff --git a/.github/workflows/test.yaml b/.github/workflows/test.yaml
index 995db271..13532247 100644
--- a/.github/workflows/test.yaml
+++ b/.github/workflows/test.yaml
@@ -99,6 +99,24 @@ jobs:
       - name: Integration tests
         run: make PROFILE=debug CERT_COMPRESSION=true integration
 
+  # TODO(@cpu): MacOS and Windows FIPS test coverage
+  fips:
+    name: FIPS
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - uses: actions/checkout@v4
+        with:
+          persist-credentials: false
+      - name: Install nightly rust toolchain
+        uses: dtolnay/rust-toolchain@nightly
+      - name: Unit tests
+        run: make FIPS=true test
+      - name: Integration tests
+        run: make FIPS=true integration
+
   test-windows-cmake-debug:
     name: Windows CMake, Debug configuration
     runs-on: windows-latest
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f460752e..79b12b90 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,8 @@ endif ()
 
 set(CERT_COMPRESSION "false" CACHE STRING "Whether to enable brotli and zlib certificate compression support")
 
+set(FIPS "false" CACHE STRING "Whether to enable aws-lc-rs and FIPS support")
+
 set(CARGO_FEATURES --no-default-features)
 if (CRYPTO_PROVIDER STREQUAL "aws-lc-rs")
     list(APPEND CARGO_FEATURES --features=aws-lc-rs)
@@ -21,6 +23,11 @@ if (CERT_COMPRESSION STREQUAL "true")
     list(APPEND CARGO_FEATURES --features=cert_compression)
 endif ()
 
+# See https://docs.rs/rustls/latest/rustls/manual/_06_fips/index.html
+if (FIPS STREQUAL "true")
+    list(APPEND CARGO_FEATURES --features=fips)
+endif ()
+
 add_subdirectory(tests)
 
 include(ExternalProject)
diff --git a/Cargo.lock b/Cargo.lock
index cfe58966..8d707e28 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -32,12 +32,28 @@ version = "1.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f1fdabc7756949593fe60f30ec81974b613357de856987752631dea1e3394c80"
 
+[[package]]
+name = "aws-lc-fips-sys"
+version = "0.12.13"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bf12b67bc9c5168f68655aadb2a12081689a58f1d9b1484705e4d1810ed6e4ac"
+dependencies = [
+ "bindgen",
+ "cc",
+ "cmake",
+ "dunce",
+ "fs_extra",
+ "libc",
+ "paste",
+]
+
 [[package]]
 name = "aws-lc-rs"
 version = "1.9.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "2f95446d919226d587817a7d21379e6eb099b97b45110a7f272a444ca5c54070"
 dependencies = [
+ "aws-lc-fips-sys",
  "aws-lc-sys",
  "mirai-annotations",
  "paste",
diff --git a/Cargo.toml b/Cargo.toml
index 1d986774..edfccc51 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -24,6 +24,7 @@ capi = []
 ring = ["rustls/ring", "webpki/ring"]
 aws-lc-rs = ["rustls/aws-lc-rs", "webpki/aws_lc_rs"]
 cert_compression = ["rustls/brotli", "rustls/zlib"]
+fips = ["aws-lc-rs", "rustls/fips"]
 
 [dependencies]
 # Keep in sync with RUSTLS_CRATE_VERSION in build.rs
diff --git a/Makefile b/Makefile
index 0eacf1d7..87831554 100644
--- a/Makefile
+++ b/Makefile
@@ -11,6 +11,7 @@ CFLAGS := -Werror -Wall -Wextra -Wpedantic -g -I src/
 PROFILE := release
 CRYPTO_PROVIDER := aws-lc-rs
 COMPRESSION := false
+FIPS := false
 DESTDIR=/usr/local
 
 ifeq ($(PROFILE), debug)
@@ -41,6 +42,11 @@ ifeq ($(COMPRESSION), true)
 	LDFLAGS += -lm
 endif
 
+# See https://docs.rs/rustls/latest/rustls/manual/_06_fips/index.html
+ifeq ($(FIPS), true)
+	CARGOFLAGS += --features fips
+endif
+
 default: target/$(PROFILE)/librustls_ffi.a
 
 all: default test integration connect-test
diff --git a/Makefile.pkg-config b/Makefile.pkg-config
index 8baf7298..08720b88 100644
--- a/Makefile.pkg-config
+++ b/Makefile.pkg-config
@@ -15,6 +15,7 @@ CFLAGS := -Werror -Wall -Wextra -Wpedantic -g -I src/
 PROFILE := release
 CRYPTO_PROVIDER := aws-lc-rs
 CERT_COMPRESSION := false
+FIPS := false
 PREFIX=/usr/local
 
 ifeq ($(PROFILE), debug)
@@ -39,6 +40,11 @@ ifeq ($(CERT_COMPRESSION), true)
 	CARGOFLAGS += --features cert_compression
 endif
 
+# See https://docs.rs/rustls/latest/rustls/manual/_06_fips/index.html
+ifeq ($(FIPS), true)
+	CARGOFLAGS += --features fips
+endif
+
 all: target/client target/server
 
 integration: all
diff --git a/cbindgen.toml b/cbindgen.toml
index b2bf782f..7c2a5966 100644
--- a/cbindgen.toml
+++ b/cbindgen.toml
@@ -14,7 +14,8 @@ include = ["rustls_tls_version"]
 "feature = read_buf" = "DEFINE_READ_BUF"
 "feature = aws-lc-rs" = "DEFINE_AWS_LC_RS"
 "feature = ring" = "DEFINE_RING"
+"feature = fips" = "DEFINE_FIPS"
 
 [parse.expand]
 crates = ["rustls-ffi"]
-features = ["read_buf", "aws-lc-rs", "ring"]
+features = ["read_buf", "aws-lc-rs", "ring", "fips"]
diff --git a/src/client.rs b/src/client.rs
index 363354b8..66b85568 100644
--- a/src/client.rs
+++ b/src/client.rs
@@ -582,6 +582,19 @@ impl rustls_client_config_builder {
 }
 
 impl rustls_client_config {
+    /// Returns true if a `rustls_connection` created from the `rustls_client_config` will
+    /// operate in FIPS mode.
+    ///
+    /// This is different from `rustls_crypto_provider_fips` which is concerned
+    /// only with cryptography, whereas this also covers TLS-level configuration that NIST
+    /// recommends, as well as ECH HPKE suites if applicable.
+    #[no_mangle]
+    pub extern "C" fn rustls_client_config_fips(config: *const rustls_client_config) -> bool {
+        ffi_panic_boundary! {
+            try_ref_from_ptr!(config).fips()
+        }
+    }
+
     /// "Free" a `rustls_client_config` previously returned from
     /// `rustls_client_config_builder_build`.
     ///
diff --git a/src/connection.rs b/src/connection.rs
index f1dc4fb4..61808814 100644
--- a/src/connection.rs
+++ b/src/connection.rs
@@ -613,6 +613,23 @@ impl rustls_connection {
         }
     }
 
+    /// Returns true if the `rustls_connection` was made with a `rustls_client_config`
+    /// or `rustls_server_config` that is FIPS compatible.
+    ///
+    /// This is different from `rustls_crypto_provider_fips` which is concerned
+    /// only with cryptography, whereas this also covers TLS-level configuration that NIST
+    /// recommends, as well as ECH HPKE suites if applicable.
+    #[no_mangle]
+    pub extern "C" fn rustls_connection_fips(conn: *const rustls_connection) -> bool {
+        ffi_panic_boundary! {
+            let conn = try_ref_from_ptr!(conn);
+            match &conn.conn {
+                rustls::Connection::Client(c) => c.fips(),
+                rustls::Connection::Server(c) => c.fips(),
+            }
+        }
+    }
+
     /// Free a rustls_connection. Calling with NULL is fine.
     /// Must not be called twice with the same value.
     #[no_mangle]
diff --git a/src/crypto_provider.rs b/src/crypto_provider.rs
index ae7a6232..e5cc92b8 100644
--- a/src/crypto_provider.rs
+++ b/src/crypto_provider.rs
@@ -248,6 +248,26 @@ pub extern "C" fn rustls_aws_lc_rs_crypto_provider() -> *const rustls_crypto_pro
     }
 }
 
+/// Return a `rustls_crypto_provider` that uses FIPS140-3 approved cryptography.
+///
+/// Using this function expresses in your code that you require FIPS-approved cryptography,
+/// and will not compile if you make a mistake with cargo features.
+///
+/// See the upstream [rustls FIPS documentation][FIPS] for more information.
+///
+/// The caller owns the returned `rustls_crypto_provider` and must free it using
+/// `rustls_crypto_provider_free`.
+///
+/// [FIPS]: https://docs.rs/rustls/latest/rustls/manual/_06_fips/index.html
+#[no_mangle]
+#[cfg(feature = "fips")]
+pub extern "C" fn rustls_default_fips_provider() -> *const rustls_crypto_provider {
+    ffi_panic_boundary! {
+        Arc::into_raw(Arc::new(rustls::crypto::default_fips_provider()))
+            as *const rustls_crypto_provider
+    }
+}
+
 /// Retrieve a pointer to the process default `rustls_crypto_provider`.
 ///
 /// This may return `NULL` if no process default provider has been set using
@@ -364,6 +384,19 @@ pub extern "C" fn rustls_crypto_provider_random(
     }
 }
 
+/// Returns true if the `rustls_crypto_provider` is operating in FIPS mode.
+///
+/// This covers only the cryptographic parts of FIPS approval. There are also
+/// TLS protocol-level recommendations made by NIST. You should prefer to call
+/// `rustls_client_config_fips` or `rustls_server_config_fips` which take these
+/// into account.
+#[no_mangle]
+pub extern "C" fn rustls_crypto_provider_fips(provider: *const rustls_crypto_provider) -> bool {
+    ffi_panic_boundary! {
+        try_ref_from_ptr!(provider).fips()
+    }
+}
+
 /// Frees the `rustls_crypto_provider`.
 ///
 /// Calling with `NULL` is fine.
diff --git a/src/rustls.h b/src/rustls.h
index f23fc013..26c18912 100644
--- a/src/rustls.h
+++ b/src/rustls.h
@@ -1758,6 +1758,16 @@ rustls_result rustls_client_config_builder_build(struct rustls_client_config_bui
  */
 void rustls_client_config_builder_free(struct rustls_client_config_builder *config);
 
+/**
+ * Returns true if a `rustls_connection` created from the `rustls_client_config` will
+ * operate in FIPS mode.
+ *
+ * This is different from `rustls_crypto_provider_fips` which is concerned
+ * only with cryptography, whereas this also covers TLS-level configuration that NIST
+ * recommends, as well as ECH HPKE suites if applicable.
+ */
+bool rustls_client_config_fips(const struct rustls_client_config *config);
+
 /**
  * "Free" a `rustls_client_config` previously returned from
  * `rustls_client_config_builder_build`.
@@ -2047,6 +2057,16 @@ rustls_result rustls_connection_read_2(struct rustls_connection *conn,
                                        size_t *out_n);
 #endif
 
+/**
+ * Returns true if the `rustls_connection` was made with a `rustls_client_config`
+ * or `rustls_server_config` that is FIPS compatible.
+ *
+ * This is different from `rustls_crypto_provider_fips` which is concerned
+ * only with cryptography, whereas this also covers TLS-level configuration that NIST
+ * recommends, as well as ECH HPKE suites if applicable.
+ */
+bool rustls_connection_fips(const struct rustls_connection *conn);
+
 /**
  * Free a rustls_connection. Calling with NULL is fine.
  * Must not be called twice with the same value.
@@ -2172,6 +2192,23 @@ const struct rustls_crypto_provider *rustls_ring_crypto_provider(void);
 const struct rustls_crypto_provider *rustls_aws_lc_rs_crypto_provider(void);
 #endif
 
+#if defined(DEFINE_FIPS)
+/**
+ * Return a `rustls_crypto_provider` that uses FIPS140-3 approved cryptography.
+ *
+ * Using this function expresses in your code that you require FIPS-approved cryptography,
+ * and will not compile if you make a mistake with cargo features.
+ *
+ * See the upstream [rustls FIPS documentation][FIPS] for more information.
+ *
+ * The caller owns the returned `rustls_crypto_provider` and must free it using
+ * `rustls_crypto_provider_free`.
+ *
+ * [FIPS]: https://docs.rs/rustls/latest/rustls/manual/_06_fips/index.html
+ */
+const struct rustls_crypto_provider *rustls_default_fips_provider(void);
+#endif
+
 /**
  * Retrieve a pointer to the process default `rustls_crypto_provider`.
  *
@@ -2233,6 +2270,16 @@ rustls_result rustls_crypto_provider_random(const struct rustls_crypto_provider
                                             uint8_t *buff,
                                             size_t len);
 
+/**
+ * Returns true if the `rustls_crypto_provider` is operating in FIPS mode.
+ *
+ * This covers only the cryptographic parts of FIPS approval. There are also
+ * TLS protocol-level recommendations made by NIST. You should prefer to call
+ * `rustls_client_config_fips` or `rustls_server_config_fips` which take these
+ * into account.
+ */
+bool rustls_crypto_provider_fips(const struct rustls_crypto_provider *provider);
+
 /**
  * Frees the `rustls_crypto_provider`.
  *
@@ -2497,6 +2544,16 @@ rustls_result rustls_server_config_builder_set_certified_keys(struct rustls_serv
 rustls_result rustls_server_config_builder_build(struct rustls_server_config_builder *builder,
                                                  const struct rustls_server_config **config_out);
 
+/**
+ * Returns true if a `rustls_connection` created from the `rustls_server_config` will
+ * operate in FIPS mode.
+ *
+ * This is different from `rustls_crypto_provider_fips` which is concerned
+ * only with cryptography, whereas this also covers TLS-level configuration that NIST
+ * recommends, as well as ECH HPKE suites if applicable.
+ */
+bool rustls_server_config_fips(const struct rustls_server_config *config);
+
 /**
  * "Free" a rustls_server_config previously returned from
  * rustls_server_config_builder_build.
diff --git a/src/server.rs b/src/server.rs
index cf5d001f..f1650f12 100644
--- a/src/server.rs
+++ b/src/server.rs
@@ -377,6 +377,19 @@ impl rustls_server_config_builder {
 }
 
 impl rustls_server_config {
+    /// Returns true if a `rustls_connection` created from the `rustls_server_config` will
+    /// operate in FIPS mode.
+    ///
+    /// This is different from `rustls_crypto_provider_fips` which is concerned
+    /// only with cryptography, whereas this also covers TLS-level configuration that NIST
+    /// recommends, as well as ECH HPKE suites if applicable.
+    #[no_mangle]
+    pub extern "C" fn rustls_server_config_fips(config: *const rustls_server_config) -> bool {
+        ffi_panic_boundary! {
+            try_ref_from_ptr!(config).fips()
+        }
+    }
+
     /// "Free" a rustls_server_config previously returned from
     /// rustls_server_config_builder_build.
     ///
diff --git a/tests/client_server.rs b/tests/client_server.rs
index 1f3d2a30..9f5e03ca 100644
--- a/tests/client_server.rs
+++ b/tests/client_server.rs
@@ -110,11 +110,17 @@ fn client_server_integration() {
         ],
     };
 
+    // CHACHA20 is not FIPS approved :)
+    #[cfg(not(feature = "fips"))]
+    let custom_ciphersuite = "TLS13_CHACHA20_POLY1305_SHA256";
+    #[cfg(feature = "fips")]
+    let custom_ciphersuite = "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256";
+
     let custom_ciphersuites = TestCase {
         name: "client/server with limited ciphersuites",
         server_opts: ServerOptions {
             valgrind: valgrind.clone(),
-            env: vec![("RUSTLS_CIPHERSUITE", "TLS13_CHACHA20_POLY1305_SHA256")],
+            env: vec![("RUSTLS_CIPHERSUITE", custom_ciphersuite)],
         },
         client_tests: vec![
             ClientTest {
@@ -122,7 +128,7 @@ fn client_server_integration() {
                 valgrind: valgrind.clone(),
                 env: vec![
                     ("NO_CHECK_CERTIFICATE", "1"),
-                    ("RUSTLS_CIPHERSUITE", "TLS13_CHACHA20_POLY1305_SHA256"),
+                    ("RUSTLS_CIPHERSUITE", custom_ciphersuite),
                 ],
                 expect_error: false,
             },