diff --git a/CMakeLists.txt b/CMakeLists.txt
index 800d76cbf..b4cb2bfc4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -66,6 +66,18 @@ if(CMAKE_C_COMPILER_ID STREQUAL "AppleClang")
     set(CMAKE_CXX_ARCHIVE_FINISH "<CMAKE_RANLIB> -no_warning_for_no_symbols -c <TARGET>")
 endif()
 
+if(APPLE)
+    find_library(CORE_FOUNDATION_FRAMEWORK CoreFoundation)
+    if(NOT CORE_FOUNDATION_FRAMEWORK)
+        message(FATAL_ERROR "Couldn't find CoreFoundation framework.")
+    endif()
+
+    find_library(SECURITY_FRAMEWORK Security)
+    if(NOT SECURITY_FRAMEWORK)
+        message(FATAL_ERROR "Couldn't find Security framework.")
+    endif()
+endif()
+
 include(CheckIncludeFile)
 
 check_include_file("arpa/inet.h" HAVE_ARPA_INET_H)
@@ -1526,6 +1538,10 @@ endif()
 
 # TODO: - Fast huge math
 
+if("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+    list(APPEND WOLFSSL_DEFINITIONS "-DWOLFSSL_X86_64_BUILD")
+endif()
+
 # SP math all
 add_option("WOLFSSL_SP_MATH_ALL"
     "Enable Single Precision math implementation for full algorithm suite (default: enabled)"
@@ -1900,6 +1916,10 @@ if(WIN32)
     # For Windows link ws2_32
     target_link_libraries(wolfssl PUBLIC
         $<$<PLATFORM_ID:Windows>:ws2_32>)
+elseif(APPLE)
+    target_link_libraries(wolfssl PUBLIC
+        ${CORE_FOUNDATION_FRAMEWORK}
+        ${SECURITY_FRAMEWORK})
 else()
     # DH requires math (m) library
     target_link_libraries(wolfssl
diff --git a/configure.ac b/configure.ac
index c61505198..0fd523e95 100644
--- a/configure.ac
+++ b/configure.ac
@@ -940,7 +940,6 @@ then
     AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_HAVE_ISSUER_NAMES"
 fi
 
-
 # liboqs
 ENABLED_LIBOQS="no"
 tryliboqsdir=""
@@ -7985,13 +7984,12 @@ then
     AM_CFLAGS="$AM_CFLAGS -DHAVE___UINT128_T=1"
 fi
 
-
 LIB_SOCKET_NSL
 AX_HARDEN_CC_COMPILER_FLAGS
 
-# if mingw then link to ws2_32 for sockets
 case $host_os in
     mingw*)
+        # if mingw then link to ws2_32 for sockets
         LDFLAGS="$LDFLAGS -lws2_32"
         if test "$enable_shared" = "yes"
         then
@@ -8001,6 +7999,10 @@ case $host_os in
                 MINGW_LIB_WARNING="yes"
             fi
         fi ;;
+    *darwin*)
+        # For Mac we need these frameworks to load system CA certs
+        LDFLAGS="$LDFLAGS -framework CoreFoundation -framework Security"
+        ;;
 esac
 
 if test "$enable_shared" = "no"; then
diff --git a/doc/dox_comments/header_files/ssl.h b/doc/dox_comments/header_files/ssl.h
index cb55ba00a..2f622f31d 100644
--- a/doc/dox_comments/header_files/ssl.h
+++ b/doc/dox_comments/header_files/ssl.h
@@ -1267,12 +1267,13 @@ const char** wolfSSL_get_system_CA_dirs(word32* num);
     \ingroup CertsKeys
 
     \brief This function attempts to load CA certificates into a WOLFSSL_CTX
-    from conventional CA cert directories, which is OS-dependent.
+    from an OS-dependent CA certificate store. Loaded certificates will be
+    trusted.
 
     \return WOLFSSL_SUCCESS on success.
     \return WOLFSSL_BAD_PATH if no system CA certs were loaded.
-    \return WOLFSSL_NOT_IMPLEMENTED if the function isn't supported for the
-    target OS.
+    \return WOLFSSL_FAILURE for other failure types (e.g. Windows cert store
+    wasn't properly closed).
 
     \param ctx pointer to the SSL context, created with wolfSSL_CTX_new().
 
diff --git a/src/ssl.c b/src/ssl.c
index 37f8aef27..13e7cb6a8 100644
--- a/src/ssl.c
+++ b/src/ssl.c
@@ -162,6 +162,15 @@
 #endif
 #endif /* !WOLFCRYPT_ONLY || OPENSSL_EXTRA */
 
+#ifdef _WIN32
+#include <Wincrypt.h>
+#pragma comment(lib, "crypt32")
+#endif
+
+#ifdef __APPLE__
+# include <Security/SecTrustSettings.h>
+#endif
+
 /*
  * OPENSSL_COMPATIBLE_DEFAULTS:
  *     Enable default behaviour that is compatible with OpenSSL. For example
@@ -8041,7 +8050,119 @@ int wolfSSL_CTX_load_verify_locations(WOLFSSL_CTX* ctx, const char* file,
     return WS_RETURN_CODE(ret,WOLFSSL_FAILURE);
 }
 
-#ifndef _WIN32
+#ifdef USE_WINDOWS_API
+
+static int LoadSystemCaCertsWindows(WOLFSSL_CTX* ctx, byte* loaded)
+{
+    int ret = WOLFSSL_SUCCESS;
+    word32 i;
+    HANDLE handle = NULL;
+    PCCERT_CONTEXT certCtx = NULL;
+    LPCSTR storeNames[2] = {"ROOT", "CA"};
+    HCRYPTPROV_LEGACY hProv = (HCRYPTPROV_LEGACY)NULL;
+
+    if (ctx == NULL || loaded == NULL) {
+        ret = WOLFSSL_FAILURE;
+    }
+
+    for (i = 0; ret == WOLFSSL_SUCCESS &&
+         i < sizeof(storeNames)/sizeof(*storeNames); ++i) {
+        handle = CertOpenSystemStoreA(hProv, storeNames[i]);
+        if (handle != NULL) {
+            while (certCtx = CertEnumCertificatesInStore(handle,
+                   certCtx)) {
+                if (certCtx->dwCertEncodingType == X509_ASN_ENCODING) {
+                    if (ProcessBuffer(ctx, certCtx->pbCertEncoded,
+                          certCtx->cbCertEncoded, WOLFSSL_FILETYPE_ASN1,
+                          CA_TYPE, NULL, NULL, 0,
+                          GET_VERIFY_SETTING_CTX(ctx)) == WOLFSSL_SUCCESS) {
+                        /*
+                         * Set "loaded" as long as we've loaded one CA
+                         * cert.
+                         */
+                        *loaded = 1;
+                    }
+                }
+            }
+        }
+        else {
+            WOLFSSL_MSG_EX("Failed to open cert store %s.", storeNames[i]);
+        }
+
+        if (handle != NULL && !CertCloseStore(handle, 0)) {
+            WOLFSSL_MSG_EX("Failed to close cert store %s.", storeNames[i]);
+            ret = WOLFSSL_FAILURE;
+        }
+    }
+
+    return ret;
+}
+
+#elif defined(__APPLE__)
+
+static int LoadSystemCaCertsMac(WOLFSSL_CTX* ctx, byte* loaded)
+{
+    int ret = WOLFSSL_SUCCESS;
+    word32 i;
+    const unsigned int trustDomains[] = {
+        kSecTrustSettingsDomainUser,
+        kSecTrustSettingsDomainAdmin,
+        kSecTrustSettingsDomainSystem
+    };
+    CFArrayRef certs;
+    OSStatus stat;
+    CFIndex numCerts;
+    CFDataRef der;
+    CFIndex j;
+
+    if (ctx == NULL || loaded == NULL) {
+        ret = WOLFSSL_FAILURE;
+    }
+
+    for (i = 0; ret == WOLFSSL_SUCCESS &&
+         i < sizeof(trustDomains)/sizeof(*trustDomains); ++i) {
+        stat = SecTrustSettingsCopyCertificates(trustDomains[i], &certs);
+
+        if (stat == errSecSuccess) {
+            numCerts = CFArrayGetCount(certs);
+            for (j = 0; j < numCerts; ++j) {
+                der = SecCertificateCopyData((SecCertificateRef)
+                          CFArrayGetValueAtIndex(certs, j));
+                if (der != NULL) {
+                    if (ProcessBuffer(ctx, CFDataGetBytePtr(der),
+                          CFDataGetLength(der), WOLFSSL_FILETYPE_ASN1,
+                          CA_TYPE, NULL, NULL, 0,
+                          GET_VERIFY_SETTING_CTX(ctx)) == WOLFSSL_SUCCESS) {
+                        /*
+                         * Set "loaded" as long as we've loaded one CA
+                         * cert.
+                         */
+                        *loaded = 1;
+                    }
+
+                    CFRelease(der);
+                }
+            }
+
+            CFRelease(certs);
+        }
+        else if (stat == errSecNoTrustSettings) {
+            WOLFSSL_MSG_EX("No trust settings for domain %d, moving to next "
+                "domain.", trustDomains[i]);
+        }
+        else {
+            WOLFSSL_MSG_EX("SecTrustSettingsCopyCertificates failed with"
+                " status %d.", stat);
+            ret = WOLFSSL_FAILURE;
+            break;
+        }
+    }
+
+    return ret;
+}
+
+#else
+
 /* Potential system CA certs directories on Linux distros. */
 static const char* systemCaDirs[] = {
     "/etc/ssl/certs",                   /* Debian, Ubuntu, Gentoo, others */
@@ -8063,53 +8184,61 @@ const char** wolfSSL_get_system_CA_dirs(word32* num)
 
     return ret;
 }
-#endif /* !_WIN32 */
+
+static int LoadSystemCaCertsNix(WOLFSSL_CTX* ctx, byte* loaded) {
+    int ret = WOLFSSL_SUCCESS;
+    word32 i;
+
+    if (ctx == NULL || loaded == NULL) {
+        ret = WOLFSSL_FAILURE;
+    }
+
+    for (i = 0; ret == WOLFSSL_SUCCESS &&
+         i < sizeof(systemCaDirs)/sizeof(*systemCaDirs); ++i) {
+        WOLFSSL_MSG_EX("Attempting to load system CA certs from %s.",
+            systemCaDirs[i]);
+        /*
+         * We want to keep trying to load more CAs even if one cert in
+         * the directory is bad and can't be used (e.g. if one is expired),
+         * so we use WOLFSSL_LOAD_FLAG_IGNORE_ERR.
+         */
+        if (wolfSSL_CTX_load_verify_locations_ex(ctx, NULL, systemCaDirs[i],
+                WOLFSSL_LOAD_FLAG_IGNORE_ERR) != WOLFSSL_SUCCESS) {
+            WOLFSSL_MSG_EX("Failed to load CA certs from %s, trying "
+                "next possible location.", systemCaDirs[i]);
+        }
+        else {
+            WOLFSSL_MSG_EX("Loaded CA certs from %s.",
+                systemCaDirs[i]);
+            *loaded = 1;
+            /* Stop searching after we've loaded one directory. */
+            break;
+        }
+    }
+
+    return ret;
+}
+
+#endif
 
 int wolfSSL_CTX_load_system_CA_certs(WOLFSSL_CTX* ctx)
 {
     int ret;
-#ifndef _WIN32
-    word32 i;
     byte loaded = 0;
-#endif
 
     WOLFSSL_ENTER("wolfSSL_CTX_load_system_CA_certs");
 
-#ifdef _WIN32
-    (void)ctx;
-    ret = WOLFSSL_NOT_IMPLEMENTED;
+#ifdef USE_WINDOWS_API
+    ret = LoadSystemCaCertsWindows(ctx, &loaded);
+#elif defined(__APPLE__)
+    ret = LoadSystemCaCertsMac(ctx, &loaded);
 #else
-    if (ctx != NULL) {
-        for (i = 0; i < sizeof(systemCaDirs)/sizeof(*systemCaDirs); ++i) {
-            WOLFSSL_MSG_EX("Attempting to load system CA certs from %s.",
-                systemCaDirs[i]);
-            /*
-             * We want to keep trying to load more CAs even if one cert in
-             * the directory is bad and can't be used (e.g. if one is expired),
-             * so we use WOLFSSL_LOAD_FLAG_IGNORE_ERR.
-             */
-            if (wolfSSL_CTX_load_verify_locations_ex(ctx, NULL, systemCaDirs[i],
-                    WOLFSSL_LOAD_FLAG_IGNORE_ERR) != WOLFSSL_SUCCESS) {
-                WOLFSSL_MSG_EX("Failed to load CA certs from %s, trying "
-                    "next possible location.", systemCaDirs[i]);
-            }
-            else {
-                WOLFSSL_MSG_EX("Loaded CA certs from %s.",
-                    systemCaDirs[i]);
-                loaded = 1;
-                /* Stop searching after we've loaded one directory. */
-                break;
-            }
-        }
-    }
+    ret = LoadSystemCaCertsNix(ctx, &loaded);
+#endif
 
-    if (loaded) {
-        ret = WOLFSSL_SUCCESS;
-    }
-    else {
+    if (ret == WOLFSSL_SUCCESS && !loaded) {
         ret = WOLFSSL_BAD_PATH;
     }
-#endif
 
     WOLFSSL_LEAVE("wolfSSL_CTX_load_system_CA_certs", ret);
 
@@ -16249,13 +16378,6 @@ cleanup:
              */
             ret = WOLFSSL_SUCCESS;
         }
-        else if (ret != WOLFSSL_SUCCESS) {
-            /*
-             * All other failure types map to WOLFSSL_FAILURE (0), same as
-             * OpenSSL.
-             */
-            ret = WOLFSSL_FAILURE;
-        }
 
         WOLFSSL_LEAVE("wolfSSL_CTX_set_default_verify_paths", ret);
 
diff --git a/tests/api.c b/tests/api.c
index 12b7f099a..e7d5b4aac 100644
--- a/tests/api.c
+++ b/tests/api.c
@@ -1352,31 +1352,26 @@ static int test_wolfSSL_CTX_load_system_CA_certs(void)
 
 #if !defined(NO_FILESYSTEM) && !defined(NO_CERTS) && !defined(NO_WOLFSSL_CLIENT)
     WOLFSSL_CTX* ctx;
+    byte dirValid = 0;
 
     ctx = wolfSSL_CTX_new(wolfSSLv23_client_method());
     if (ctx == NULL) {
+        fprintf(stderr, "wolfSSL_CTX_new failed.\n");
         ret = -1;
     }
     if (ret == 0) {
-#ifdef _WIN32
-        if (wolfSSL_CTX_load_system_CA_certs(ctx) != WOLFSSL_NOT_IMPLEMENTED) {
-            ret = -1;
-        }
-#ifdef OPENSSL_EXTRA
-        if (wolfSSL_CTX_set_default_verify_paths(ctx) != WOLFSSL_FAILURE) {
-            ret = -1;
-        }
-#endif /* OPENSSL_EXTRA */
-#else
+    #if defined(USE_WINDOWS_API) || defined(__APPLE__)
+        dirValid = 1;
+    #else
         word32 numDirs;
         const char** caDirs = wolfSSL_get_system_CA_dirs(&numDirs);
 
         if (caDirs == NULL || numDirs == 0) {
+            fprintf(stderr, "wolfSSL_get_system_CA_dirs failed.\n");
             ret = -1;
         }
         else {
             ReadDirCtx dirCtx;
-            byte dirValid = 0;
             word32 i;
 
             for (i = 0; i < numDirs; ++i) {
@@ -1387,29 +1382,26 @@ static int test_wolfSSL_CTX_load_system_CA_certs(void)
                     break;
                 }
             }
-
-            /*
-             * If the directory isn't empty, we should be able to load CA
-             * certs from it.
-             */
-            if (dirValid && wolfSSL_CTX_load_system_CA_certs(ctx) !=
-                WOLFSSL_SUCCESS) {
-                ret = -1;
-            }
-        #ifdef OPENSSL_EXTRA
-            /*
-             * Even if we don't have a valid directory to load system CA
-             * certs from, the OpenSSL compat layer function should return
-             * success.
-             */
-            if (wolfSSL_CTX_set_default_verify_paths(ctx)
-                != WOLFSSL_SUCCESS) {
-                ret = -1;
-            }
-        #endif /* OPENSSL_EXTRA */
         }
-#endif /* _WIN32 */
+    #endif
     }
+    /*
+     * If the directory isn't empty, we should be able to load CA
+     * certs from it. On Windows/Mac, we assume the CA cert stores are
+     * usable.
+     */
+    if (ret == 0 && dirValid && wolfSSL_CTX_load_system_CA_certs(ctx) !=
+        WOLFSSL_SUCCESS) {
+        fprintf(stderr, "wolfSSL_CTX_load_system_CA_certs failed.\n");
+        ret = -1;
+    }
+#ifdef OPENSSL_EXTRA
+    if (ret == 0 &&
+        wolfSSL_CTX_set_default_verify_paths(ctx) != WOLFSSL_SUCCESS) {
+        fprintf(stderr, "wolfSSL_CTX_set_default_verify_paths failed.\n");
+        ret = -1;
+    }
+#endif /* OPENSSL_EXTRA */
 
     wolfSSL_CTX_free(ctx);
 #endif /* !NO_FILESYSTEM && !NO_CERTS && !NO_WOLFSSL_CLIENT */