diff --git a/BUILD.generated_tests.bzl b/BUILD.generated_tests.bzl
index 2c5498deb..2eed380b6 100644
--- a/BUILD.generated_tests.bzl
+++ b/BUILD.generated_tests.bzl
@@ -193,6 +193,7 @@ crypto_test_sources = [
     "src/crypto/pkcs8/pkcs8_test.cc",
     "src/crypto/poly1305/poly1305_test.cc",
     "src/crypto/pool/pool_test.cc",
+    "src/crypto/rand_extra/getentropy_test.cc",
     "src/crypto/rand_extra/rand_test.cc",
     "src/crypto/refcount_test.cc",
     "src/crypto/rsa_extra/rsa_test.cc",
diff --git a/sources.json b/sources.json
index 2b661fdf2..faf0a28ca 100644
--- a/sources.json
+++ b/sources.json
@@ -603,6 +603,7 @@
     "src/crypto/pkcs8/pkcs8_test.cc", 
     "src/crypto/poly1305/poly1305_test.cc", 
     "src/crypto/pool/pool_test.cc", 
+    "src/crypto/rand_extra/getentropy_test.cc", 
     "src/crypto/rand_extra/rand_test.cc", 
     "src/crypto/refcount_test.cc", 
     "src/crypto/rsa_extra/rsa_test.cc", 
diff --git a/src/crypto/rand_extra/getentropy_test.cc b/src/crypto/rand_extra/getentropy_test.cc
new file mode 100644
index 000000000..d6919139a
--- /dev/null
+++ b/src/crypto/rand_extra/getentropy_test.cc
@@ -0,0 +1,65 @@
+/* Copyright (c) 2023, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#if !defined(_DEFAULT_SOURCE)
+#define _DEFAULT_SOURCE  // Needed for getentropy on musl and glibc
+#endif
+
+#include <openssl/rand.h>
+
+#include "../fipsmodule/rand/internal.h"
+
+#if defined(OPENSSL_RAND_GETENTROPY)
+
+#include <unistd.h>
+
+#include <sys/errno.h>
+
+#if defined(OPENSSL_MACOS) || defined(OPENSSL_FUCHSIA)
+#include <sys/random.h>
+#endif
+
+#include <gtest/gtest.h>
+
+#include <openssl/span.h>
+
+#include "../test/test_util.h"
+
+// This test is, strictly speaking, flaky, but we use large enough buffers
+// that the probability of failing when we should pass is negligible.
+
+TEST(GetEntropyTest, NotObviouslyBroken) {
+  static const uint8_t kZeros[256] = {0};
+
+  uint8_t buf1[256], buf2[256];
+
+  EXPECT_EQ(getentropy(buf1, sizeof(buf1)), 0);
+  EXPECT_EQ(getentropy(buf2, sizeof(buf2)), 0);
+  EXPECT_NE(Bytes(buf1), Bytes(buf2));
+  EXPECT_NE(Bytes(buf1), Bytes(kZeros));
+  EXPECT_NE(Bytes(buf2), Bytes(kZeros));
+  uint8_t buf3[256];
+  // Ensure that the implementation is not simply returning the memory unchanged.
+  memcpy(buf3, buf1, sizeof(buf3));
+  EXPECT_EQ(getentropy(buf1, sizeof(buf1)), 0);
+  EXPECT_NE(Bytes(buf1), Bytes(buf3));
+  errno = 0;
+  uint8_t toobig[257];
+  // getentropy should fail returning -1 and setting errno to EIO if you request
+  // more than 256 bytes of entropy. macOS's man page says EIO but it actually
+  // returns EINVAL, so we accept either.
+  EXPECT_EQ(getentropy(toobig, 257), -1);
+  EXPECT_TRUE(errno == EIO || errno == EINVAL);
+}
+#endif
diff --git a/src/sources.cmake b/src/sources.cmake
index 3153efc01..1ebc44ad3 100644
--- a/src/sources.cmake
+++ b/src/sources.cmake
@@ -60,6 +60,7 @@ set(
   crypto/poly1305/poly1305_test.cc
   crypto/pool/pool_test.cc
   crypto/rand_extra/rand_test.cc
+  crypto/rand_extra/getentropy_test.cc
   crypto/refcount_test.cc
   crypto/rsa_extra/rsa_test.cc
   crypto/self_test.cc