diff --git a/.arclint b/.arclint
--- a/.arclint
+++ b/.arclint
@@ -172,6 +172,13 @@
         "lint-logs": {
             "type": "lint-logs",
             "include": "(^src/.*\\.(h|cpp)$)"
+        },
+        "lint-qt": {
+            "type": "lint-qt",
+            "include": "(^src/qt/.*\\.(h|cpp)$)",
+            "exclude": [
+                "(^src/qt/(locale|forms|res)/)"
+            ]
         }
     }
 }
diff --git a/arcanist/.phutil_module_cache b/arcanist/.phutil_module_cache
--- a/arcanist/.phutil_module_cache
+++ b/arcanist/.phutil_module_cache
@@ -1 +1 @@
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\ No newline at end of file
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\ No newline at end of file
diff --git a/arcanist/__phutil_library_map__.php b/arcanist/__phutil_library_map__.php
--- a/arcanist/__phutil_library_map__.php
+++ b/arcanist/__phutil_library_map__.php
@@ -31,6 +31,7 @@
     'PythonFormatLinter' => 'linter/PythonFormatLinter.php',
     'PythonOpenFileEncodingLinter' => 'linter/PythonOpenFileEncodingLinter.php',
     'PythonShebangLinter' => 'linter/PythonShebangLinter.php',
+    'Qt5Linter' => 'linter/Qt5Linter.php',
     'ShellCheckLinter' => 'linter/ShellCheckLinter.php',
     'ShellLocaleLinter' => 'linter/ShellLocaleLinter.php',
     'StdintLinter' => 'linter/StdintLinter.php',
@@ -62,6 +63,7 @@
     'PythonFormatLinter' => 'ArcanistExternalLinter',
     'PythonOpenFileEncodingLinter' => 'ArcanistLinter',
     'PythonShebangLinter' => 'ArcanistLinter',
+    'Qt5Linter' => 'ArcanistLinter',
     'ShellCheckLinter' => 'ArcanistExternalLinter',
     'ShellLocaleLinter' => 'ArcanistLinter',
     'StdintLinter' => 'ArcanistLinter',
diff --git a/arcanist/linter/Qt5Linter.php b/arcanist/linter/Qt5Linter.php
new file mode 100644
--- /dev/null
+++ b/arcanist/linter/Qt5Linter.php
@@ -0,0 +1,55 @@
+<?php
+
+/**
+ * Enforces Qt5 SIGNAL/SLOT connect style
+ */
+
+final class Qt5Linter extends ArcanistLinter {
+
+  const QT4_CONNECT_SYNTAX_FOUND = 1;
+
+  public function getInfoName() {
+    return 'lint-qt';
+  }
+
+  public function getInfoDescription() {
+    return pht('Check qt files for regressions in SIGNAL/SLOT connection '.
+               'styles from Qt5 to Qt4.');
+  }
+
+  public function getLinterName() {
+    return 'lint-qt';
+  }
+
+  public function getLinterConfigurationName() {
+    return 'lint-qt';
+  }
+
+  public function getLintSeverityMap() {
+    return array(
+      self::QT4_CONNECT_SYNTAX_FOUND => ArcanistLintSeverity::SEVERITY_ERROR);
+  }
+
+  public function getLintNameMap() {
+    return array(
+      self::QT4_CONNECT_SYNTAX_FOUND => pht('Qt5 SIGNAL/SLOT violation'));
+  }
+
+  public function lintPath($path) {
+    $path = Filesystem::resolvePath($path, $this->getProjectRoot());
+    $fileContent = Filesystem::readFile($path);
+
+    $pattern = '/,\s*(SIGNAL|SLOT)/';
+    if(preg_match_all($pattern, $fileContent, $matches, PREG_OFFSET_CAPTURE)) {
+      foreach($matches[1] as $match) {
+        list($qt4syntax, $offset) = $match;
+        $this->raiseLintAtOffset(
+          $offset,
+          self::QT4_CONNECT_SYNTAX_FOUND,
+          pht('Qt connect style must match Qt5 connect style.'),
+          $qt4syntax,
+          null);
+      }
+    }
+  }
+}