diff --git a/ext/standard/proc_open.c b/ext/standard/proc_open.c
index 55f4dd484958..d0f40db0f78a 100644
--- a/ext/standard/proc_open.c
+++ b/ext/standard/proc_open.c
@@ -302,11 +302,13 @@ static void proc_open_rsrc_dtor(zend_resource *rsrc)
 
 	if (wait_pid <= 0) {
 		FG(pclose_ret) = -1;
+	} else if (WIFEXITED(wstatus)) {
+		FG(pclose_ret) = WEXITSTATUS(wstatus);
+	} else if (WIFSIGNALED(wstatus)) {
+		/* Follow the bash/shell convention: 128 + signal number */
+		FG(pclose_ret) = 128 + WTERMSIG(wstatus);
 	} else {
-		if (WIFEXITED(wstatus)) {
-			wstatus = WEXITSTATUS(wstatus);
-		}
-		FG(pclose_ret) = wstatus;
+		FG(pclose_ret) = -1;
 	}
 
 #else
diff --git a/ext/standard/tests/general_functions/proc_close_signal_exit_code.phpt b/ext/standard/tests/general_functions/proc_close_signal_exit_code.phpt
new file mode 100644
index 000000000000..ad1765150c15
--- /dev/null
+++ b/ext/standard/tests/general_functions/proc_close_signal_exit_code.phpt
@@ -0,0 +1,44 @@
+--TEST--
+proc_close() returns 128+signal when child is killed by a signal
+--SKIPIF--
+<?php
+if (PHP_OS_FAMILY === 'Windows') die('skip Not for Windows');
+if (!is_executable('/bin/sh')) die('skip /bin/sh not available');
+?>
+--FILE--
+<?php
+
+// Shell that kills itself with SIGKILL (9) — cannot be caught
+$process = proc_open(
+    ['/bin/sh', '-c', 'kill -9 $$'],
+    [['pipe', 'r'], ['pipe', 'w'], ['pipe', 'w']],
+    $pipes
+);
+
+foreach ($pipes as $pipe) {
+    fclose($pipe);
+}
+
+$exitCode = proc_close($process);
+// Should be 128 + 9 = 137
+var_dump($exitCode);
+
+// Child that exits normally with code 42
+$process2 = proc_open(
+    ['/bin/sh', '-c', 'exit 42'],
+    [['pipe', 'r'], ['pipe', 'w'], ['pipe', 'w']],
+    $pipes2
+);
+
+foreach ($pipes2 as $pipe) {
+    fclose($pipe);
+}
+
+$exitCode2 = proc_close($process2);
+// Should be 42
+var_dump($exitCode2);
+
+?>
+--EXPECT--
+int(137)
+int(42)