diff --git a/src/cfgparse.l b/src/cfgparse.l
index 2e1d240a..4cf1a1c3 100644
--- a/src/cfgparse.l
+++ b/src/cfgparse.l
@@ -167,6 +167,7 @@ ctrl                            { return TOKCONTROL; }
 shift                           { return TOKSHIFT; }
 
 class                           { yy_push_state(WANT_QSTRING); return TOK_CLASS; }
+instance                        { yy_push_state(WANT_QSTRING); return TOK_INSTANCE; }
 id                              { yy_push_state(WANT_QSTRING); return TOK_ID; }
 con_id                          { yy_push_state(WANT_QSTRING); return TOK_CON_ID; }
 con_mark                        { yy_push_state(WANT_QSTRING); return TOK_MARK; }
diff --git a/src/cfgparse.y b/src/cfgparse.y
index 38f306e9..59b22c6c 100644
--- a/src/cfgparse.y
+++ b/src/cfgparse.y
@@ -547,6 +547,7 @@ void parse_file(const char *f) {
 
 %token              TOK_MARK            "mark"
 %token              TOK_CLASS           "class"
+%token              TOK_INSTANCE        "instance"
 %token              TOK_ID              "id"
 %token              TOK_CON_ID          "con_id"
 %token              TOK_TITLE           "title"
@@ -694,6 +695,11 @@ criterion:
         printf("criteria: class = %s\n", $3);
         current_match.class = $3;
     }
+    | TOK_INSTANCE '=' STR
+    {
+        printf("criteria: instance = %s\n", $3);
+        current_match.instance = $3;
+    }
     | TOK_CON_ID '=' STR
     {
         printf("criteria: id = %s\n", $3);
diff --git a/src/cmdparse.l b/src/cmdparse.l
index 898416c2..6c756b0d 100644
--- a/src/cmdparse.l
+++ b/src/cmdparse.l
@@ -153,6 +153,7 @@ false                           { return TOK_DISABLE; }
 no                              { return TOK_DISABLE; }
 
 class                           { BEGIN(WANT_QSTRING); return TOK_CLASS; }
+instance                        { BEGIN(WANT_QSTRING); return TOK_INSTANCE; }
 id                              { BEGIN(WANT_QSTRING); return TOK_ID; }
 con_id                          { BEGIN(WANT_QSTRING); return TOK_CON_ID; }
 con_mark                        { BEGIN(WANT_QSTRING); return TOK_MARK; }
diff --git a/src/cmdparse.y b/src/cmdparse.y
index e115f3e5..32558f2e 100644
--- a/src/cmdparse.y
+++ b/src/cmdparse.y
@@ -175,6 +175,7 @@ bool definitelyGreaterThan(float a, float b, float epsilon) {
 %token              TOK_NOP             "nop"
 
 %token              TOK_CLASS           "class"
+%token              TOK_INSTANCE        "instance"
 %token              TOK_ID              "id"
 %token              TOK_CON_ID          "con_id"
 %token              TOK_TITLE           "title"
@@ -300,6 +301,11 @@ criterion:
         printf("criteria: class = %s\n", $3);
         current_match.class = $3;
     }
+    | TOK_INSTANCE '=' STR
+    {
+        printf("criteria: instance = %s\n", $3);
+        current_match.instance = $3;
+    }
     | TOK_CON_ID '=' STR
     {
         printf("criteria: id = %s\n", $3);
diff --git a/testcases/t/65-for_window.t b/testcases/t/65-for_window.t
index f156f11b..2fb85dfa 100644
--- a/testcases/t/65-for_window.t
+++ b/testcases/t/65-for_window.t
@@ -244,6 +244,73 @@ cmp_ok(@content, '==', 1, 'one node on this workspace now');
 is($content[0]->{border}, 'normal', 'no border');
 
 
+exit_gracefully($process->pid);
+
+##############################################################
+# 5: check that a class criterion does not match the instance
+##############################################################
+
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="foo"] border 1pixel
+EOT
+
+$process = launch_with_config($config);
+
+$tmp = fresh_workspace;
+
+$window = $x->root->create_child(
+    class => WINDOW_CLASS_INPUT_OUTPUT,
+    rect => [ 0, 0, 30, 30 ],
+    background_color => '#00ff00',
+);
+
+$window->_create;
+
+set_wm_class($window->id, 'bar', 'foo');
+$window->name('usethis');
+$window->map;
+sleep 0.25;
+
+@content = @{get_ws_content($tmp)};
+cmp_ok(@content, '==', 1, 'one node on this workspace now');
+is($content[0]->{border}, 'normal', 'normal border, not matched');
+
+exit_gracefully($process->pid);
+
+##############################################################
+# 6: check that the 'instance' criterion works
+##############################################################
+
+$config = <<EOT;
+# i3 config file (v4)
+font -misc-fixed-medium-r-normal--13-120-75-75-C-70-iso10646-1
+for_window [class="foo"] border 1pixel
+for_window [instance="foo"] border none
+EOT
+
+$process = launch_with_config($config);
+
+$tmp = fresh_workspace;
+
+$window = $x->root->create_child(
+    class => WINDOW_CLASS_INPUT_OUTPUT,
+    rect => [ 0, 0, 30, 30 ],
+    background_color => '#00ff00',
+);
+
+$window->_create;
+
+set_wm_class($window->id, 'bar', 'foo');
+$window->name('usethis');
+$window->map;
+sleep 0.25;
+
+@content = @{get_ws_content($tmp)};
+cmp_ok(@content, '==', 1, 'one node on this workspace now');
+is($content[0]->{border}, 'none', 'no border');
+
 exit_gracefully($process->pid);
 
 done_testing;