diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index fbf14dd4d62..94155f51d0c 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,9 @@
+2017-08-15  Sergio Durigan Junior  <sergiodj@redhat.com>
+
+	PR gdb/21954
+	* infcmd.c (unset_environment_command): Use the 'clear' method on
+	the environment instead of resetting it.
+
 2017-08-15  John Baldwin  <jhb@FreeBSD.org>
 
 	* fbsd-nat.c (fbsd_convert_siginfo): Fix compile on big-endian
diff --git a/gdb/infcmd.c b/gdb/infcmd.c
index defa7b0c48c..c8a82db4552 100644
--- a/gdb/infcmd.c
+++ b/gdb/infcmd.c
@@ -2230,7 +2230,7 @@ unset_environment_command (char *var, int from_tty)
       /* If there is no argument, delete all environment variables.
          Ask for confirmation if reading from the terminal.  */
       if (!from_tty || query (_("Delete all environment variables? ")))
-	current_inferior ()->environment = gdb_environ::from_host_environ ();
+	current_inferior ()->environment.clear ();
     }
   else
     current_inferior ()->environment.unset (var);
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index f9494af9386..39c49b8d0ea 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2017-08-15  Sergio Durigan Junior  <sergiodj@redhat.com>
+
+	PR gdb/21954
+	* gdb.base/environ.exp: Add test to check if 'unset environment'
+	works.
+
 2017-08-14  Andreas Arnez  <arnez@linux.vnet.ibm.com>
 
 	* lib/gdb.exp (universal_compile_options): New caching proc.
diff --git a/gdb/testsuite/gdb.base/environ.exp b/gdb/testsuite/gdb.base/environ.exp
index 0b69a80a902..bb52063b297 100644
--- a/gdb/testsuite/gdb.base/environ.exp
+++ b/gdb/testsuite/gdb.base/environ.exp
@@ -46,6 +46,9 @@ gdb_test "unset environment" "" "unset all environment variables" \
     "Delete all environment variables. .y or n. $" \
     "y"
 
+gdb_test_no_output "show environment" \
+    "all environment variables have been unset"
+
 # Verify that we can set a specific environment variable.
 test_set_show_env_var "EDITOR" "emacs" "set environment variable"