diff --git a/src/core/BUILD.gn b/src/core/BUILD.gn
index 89a989229..616bb9417 100644
--- a/src/core/BUILD.gn
+++ b/src/core/BUILD.gn
@@ -669,6 +669,7 @@ source_set("libopenthread_core_config") {
     "config/diag.h",
     "config/dns_client.h",
     "config/dnssd_server.h",
+    "config/dtls.h",
     "config/ip6.h",
     "config/joiner.h",
     "config/link_quality.h",
diff --git a/src/core/Makefile.am b/src/core/Makefile.am
index fb5dfe70d..96387d50f 100644
--- a/src/core/Makefile.am
+++ b/src/core/Makefile.am
@@ -407,6 +407,7 @@ HEADERS_COMMON                                  = \
     config/diag.h                                 \
     config/dns_client.h                           \
     config/dnssd_server.h                         \
+    config/dtls.h                                 \
     config/ip6.h                                  \
     config/joiner.h                               \
     config/link_quality.h                         \
diff --git a/src/core/config/dtls.h b/src/core/config/dtls.h
new file mode 100644
index 000000000..e27918c72
--- /dev/null
+++ b/src/core/config/dtls.h
@@ -0,0 +1,60 @@
+/*
+ *  Copyright (c) 2021, The OpenThread Authors.
+ *  All rights reserved.
+ *
+ *  Redistribution and use in source and binary forms, with or without
+ *  modification, are permitted provided that the following conditions are met:
+ *  1. Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *  2. Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ *  3. Neither the name of the copyright holder nor the
+ *     names of its contributors may be used to endorse or promote products
+ *     derived from this software without specific prior written permission.
+ *
+ *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ *  AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ *  ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ *  LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ *  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ *  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ *  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ *  POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/**
+ * @file
+ *   This file includes compile-time configurations for DTLS.
+ *
+ */
+
+#ifndef CONFIG_DTLS_H_
+#define CONFIG_DTLS_H_
+
+#include "config/border_router.h"
+#include "config/coap.h"
+#include "config/commissioner.h"
+#include "config/joiner.h"
+
+/**
+ * @def OPENTHREAD_CONFIG_DTLS_MAX_CONTENT_LEN
+ *
+ * The max length of the OpenThread dtls content buffer.
+ *
+ */
+#ifndef OPENTHREAD_CONFIG_DTLS_MAX_CONTENT_LEN
+#define OPENTHREAD_CONFIG_DTLS_MAX_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
+#endif
+
+#if OPENTHREAD_CONFIG_COAP_SECURE_API_ENABLE || OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE || \
+    OPENTHREAD_CONFIG_COMMISSIONER_ENABLE || OPENTHREAD_CONFIG_JOINER_ENABLE
+#define OPENTHREAD_CONFIG_DTLS_ENABLE 1
+#else
+#define OPENTHREAD_CONFIG_DTLS_ENABLE 0
+#endif
+
+#endif // CONFIG_DTLS_H_
diff --git a/src/core/meshcop/dtls.cpp b/src/core/meshcop/dtls.cpp
index e10096a51..1bdbc5c9b 100644
--- a/src/core/meshcop/dtls.cpp
+++ b/src/core/meshcop/dtls.cpp
@@ -781,7 +781,7 @@ void Dtls::HandleTimer(void)
 
 void Dtls::Process(void)
 {
-    uint8_t buf[MBEDTLS_SSL_MAX_CONTENT_LEN];
+    uint8_t buf[OPENTHREAD_CONFIG_DTLS_MAX_CONTENT_LEN];
     bool    shouldDisconnect = false;
     int     rval;
 
diff --git a/src/core/openthread-core-config.h b/src/core/openthread-core-config.h
index d17a01496..acac4a622 100644
--- a/src/core/openthread-core-config.h
+++ b/src/core/openthread-core-config.h
@@ -66,6 +66,7 @@
 #include "config/diag.h"
 #include "config/dns_client.h"
 #include "config/dnssd_server.h"
+#include "config/dtls.h"
 #include "config/ip6.h"
 #include "config/joiner.h"
 #include "config/link_quality.h"
@@ -82,13 +83,6 @@
 #include "config/time_sync.h"
 #include "config/tmf.h"
 
-#if OPENTHREAD_CONFIG_COAP_SECURE_API_ENABLE || OPENTHREAD_CONFIG_BORDER_AGENT_ENABLE || \
-    OPENTHREAD_CONFIG_COMMISSIONER_ENABLE || OPENTHREAD_CONFIG_JOINER_ENABLE
-#define OPENTHREAD_CONFIG_DTLS_ENABLE 1
-#else
-#define OPENTHREAD_CONFIG_DTLS_ENABLE 0
-#endif
-
 #undef OPENTHREAD_CORE_CONFIG_H_IN
 
 #include "config/openthread-core-config-check.h"