diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 362117fd9a..2408fd1211 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -1185,6 +1185,7 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush );
 int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl );
 
 int mbedtls_ssl_tls13_process_finished_message( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_tls13_write_finished_message( mbedtls_ssl_context *ssl );
 
 int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl );
diff --git a/library/ssl_tls13_client.c b/library/ssl_tls13_client.c
index 6deab2a8c7..a2e5f33a0d 100644
--- a/library/ssl_tls13_client.c
+++ b/library/ssl_tls13_client.c
@@ -1611,6 +1611,7 @@ static int ssl_tls1_3_process_server_finished( mbedtls_ssl_context *ssl )
     if( ret != 0 )
         return( ret );
 
+    mbedtls_ssl_set_outbound_transform( ssl, ssl->handshake->transform_handshake );
     mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_FINISHED );
     return( 0 );
 }
@@ -1618,9 +1619,14 @@ static int ssl_tls1_3_process_server_finished( mbedtls_ssl_context *ssl )
 /*
  * Handler for MBEDTLS_SSL_CLIENT_FINISHED
  */
-static int ssl_tls1_3_write_client_finished( mbedtls_ssl_context *ssl )
+static int ssl_tls13_write_client_finished( mbedtls_ssl_context *ssl )
 {
-    MBEDTLS_SSL_DEBUG_MSG( 1, ( "%s hasn't been implemented", __func__ ) );
+    int ret;
+
+    ret = mbedtls_ssl_tls13_write_finished_message( ssl );
+    if( ret != 0 )
+        return( ret );
+
     mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_FLUSH_BUFFERS );
     return( 0 );
 }
@@ -1689,7 +1695,7 @@ int mbedtls_ssl_tls13_handshake_client_step( mbedtls_ssl_context *ssl )
             break;
 
         case MBEDTLS_SSL_CLIENT_FINISHED:
-            ret = ssl_tls1_3_write_client_finished( ssl );
+            ret = ssl_tls13_write_client_finished( ssl );
             break;
 
         case MBEDTLS_SSL_FLUSH_BUFFERS:
diff --git a/library/ssl_tls13_generic.c b/library/ssl_tls13_generic.c
index b2a70f3cdd..f17bf994c2 100644
--- a/library/ssl_tls13_generic.c
+++ b/library/ssl_tls13_generic.c
@@ -29,6 +29,7 @@
 #include "mbedtls/debug.h"
 #include "mbedtls/oid.h"
 #include "mbedtls/platform.h"
+#include <string.h>
 
 #include "ssl_misc.h"
 #include "ssl_tls13_keys.h"
@@ -974,7 +975,7 @@ cleanup:
 }
 #endif /* MBEDTLS_SSL_CLI_C */
 
-static int ssl_tls13_postprocess_finished_message( mbedtls_ssl_context* ssl )
+static int ssl_tls13_postprocess_finished_message( mbedtls_ssl_context *ssl )
 {
 
 #if defined(MBEDTLS_SSL_CLI_C)
@@ -1014,6 +1015,93 @@ cleanup:
     return( ret );
 }
 
+/*
+ *
+ * STATE HANDLING: Write and send Finished message.
+ *
+ */
+/*
+ * Implement
+ */
+
+static int ssl_tls13_prepare_finished_message( mbedtls_ssl_context *ssl )
+{
+    int ret;
+
+    /* Compute transcript of handshake up to now. */
+    ret = mbedtls_ssl_tls13_calculate_verify_data( ssl,
+                    ssl->handshake->state_local.finished_out.digest,
+                    sizeof( ssl->handshake->state_local.finished_out.digest ),
+                    &ssl->handshake->state_local.finished_out.digest_len,
+                    ssl->conf->endpoint );
+
+    if( ret != 0 )
+    {
+         MBEDTLS_SSL_DEBUG_RET( 1, "calculate_verify_data failed", ret );
+        return( ret );
+    }
+
+    return( 0 );
+}
+
+static int ssl_tls13_finalize_finished_message( mbedtls_ssl_context *ssl )
+{
+    // TODO: Add back resumption keys calculation after MVP.
+    ((void) ssl);
+
+    return( 0 );
+}
+
+static int ssl_tls13_write_finished_message_body( mbedtls_ssl_context *ssl,
+                                                  unsigned char *buf,
+                                                  unsigned char *end,
+                                                  size_t *olen )
+{
+    size_t verify_data_len = ssl->handshake->state_local.finished_out.digest_len;
+    /*
+     * struct {
+     *     opaque verify_data[Hash.length];
+     * } Finished;
+     */
+    MBEDTLS_SSL_CHK_BUF_PTR( buf, end, verify_data_len );
+
+    memcpy( buf, ssl->handshake->state_local.finished_out.digest,
+            verify_data_len );
+
+    *olen = verify_data_len;
+    return( 0 );
+}
+
+/* Main entry point: orchestrates the other functions */
+int mbedtls_ssl_tls13_write_finished_message( mbedtls_ssl_context *ssl )
+{
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    unsigned char *buf;
+    size_t buf_len, msg_len;
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write finished message" ) );
+
+    MBEDTLS_SSL_PROC_CHK( ssl_tls13_prepare_finished_message( ssl ) );
+
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_start_handshake_msg( ssl,
+                              MBEDTLS_SSL_HS_FINISHED, &buf, &buf_len ) );
+
+    MBEDTLS_SSL_PROC_CHK( ssl_tls13_write_finished_message_body(
+                              ssl, buf, buf + buf_len, &msg_len ) );
+
+    mbedtls_ssl_tls1_3_add_hs_msg_to_checksum( ssl, MBEDTLS_SSL_HS_FINISHED,
+                                               buf, msg_len );
+
+    MBEDTLS_SSL_PROC_CHK( ssl_tls13_finalize_finished_message( ssl ) );
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_tls13_finish_handshake_msg( ssl,
+                                              buf_len, msg_len ) );
+    MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_flush_output( ssl ) );
+
+cleanup:
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write finished message" ) );
+    return( ret );
+}
 
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */