diff --git a/src/protocolbuffers/generator/php/MessageGenerator.php b/src/protocolbuffers/generator/php/MessageGenerator.php
index 8f144e7..fba2cfd 100644
--- a/src/protocolbuffers/generator/php/MessageGenerator.php
+++ b/src/protocolbuffers/generator/php/MessageGenerator.php
@@ -543,7 +543,7 @@ public function generate(Printer $printer)
             if ($dict->getLeadingComments()) {
                 $lines = preg_split("/\r?\n/", trim($dict->getLeadingComments()));
                 foreach ($lines as $line) {
-                    if ($line[0] == " ") {
+                    if ($line && $line[0] == " ") {
                         $line = substr($line, 1);
                     }
                     $printer->put(" * `comment`\n", "comment", $line);