diff --git a/src/__phutil_library_map__.php b/src/__phutil_library_map__.php
--- a/src/__phutil_library_map__.php
+++ b/src/__phutil_library_map__.php
@@ -315,6 +315,8 @@
     'ArcanistTasksWorkflow' => 'workflow/ArcanistTasksWorkflow.php',
     'ArcanistTautologicalExpressionXHPASTLinterRule' => 'lint/linter/xhpast/rules/ArcanistTautologicalExpressionXHPASTLinterRule.php',
     'ArcanistTautologicalExpressionXHPASTLinterRuleTestCase' => 'lint/linter/xhpast/rules/__tests__/ArcanistTautologicalExpressionXHPASTLinterRuleTestCase.php',
+    'ArcanistTernaryExpressionSpacingXHPASTLinterRule' => 'lint/linter/xhpast/rules/ArcanistTernaryExpressionSpacingXHPASTLinterRule.php',
+    'ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase' => 'lint/linter/xhpast/rules/__tests__/ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase.php',
     'ArcanistTestResultParser' => 'unit/parser/ArcanistTestResultParser.php',
     'ArcanistTestXHPASTLintSwitchHook' => 'lint/linter/__tests__/ArcanistTestXHPASTLintSwitchHook.php',
     'ArcanistTextLinter' => 'lint/linter/ArcanistTextLinter.php',
@@ -693,6 +695,8 @@
     'ArcanistTasksWorkflow' => 'ArcanistWorkflow',
     'ArcanistTautologicalExpressionXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
     'ArcanistTautologicalExpressionXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
+    'ArcanistTernaryExpressionSpacingXHPASTLinterRule' => 'ArcanistXHPASTLinterRule',
+    'ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase' => 'ArcanistXHPASTLinterRuleTestCase',
     'ArcanistTestResultParser' => 'Phobject',
     'ArcanistTestXHPASTLintSwitchHook' => 'ArcanistXHPASTLintSwitchHook',
     'ArcanistTextLinter' => 'ArcanistLinter',
diff --git a/src/lint/linter/xhpast/rules/ArcanistTernaryExpressionSpacingXHPASTLinterRule.php b/src/lint/linter/xhpast/rules/ArcanistTernaryExpressionSpacingXHPASTLinterRule.php
new file mode 100644
--- /dev/null
+++ b/src/lint/linter/xhpast/rules/ArcanistTernaryExpressionSpacingXHPASTLinterRule.php
@@ -0,0 +1,60 @@
+<?php
+
+final class ArcanistTernaryExpressionSpacingXHPASTLinterRule
+  extends ArcanistXHPASTLinterRule {
+
+  const ID = 93;
+
+  public function getLintName() {
+    return pht('Space Around Ternary Operator');
+  }
+
+  public function getLintSeverity() {
+    return ArcanistLintSeverity::SEVERITY_WARNING;
+  }
+
+  public function process(XHPASTNode $root) {
+    $expressions = $root->selectDescendantsOfType('n_TERNARY_EXPRESSION');
+
+    foreach ($expressions as $expression) {
+      $operators = $expression->selectTokensOfTypes(array('?', ':'));
+      $shorthand = $expression->getChildByIndex(2)->getTypeName() == 'n_EMPTY';
+
+      foreach ($operators as $operator) {
+        $before = $operator->getNonsemanticTokensBefore();
+        $after  = $operator->getNonsemanticTokensBefore();
+
+        $operator_value = $operator->getValue();
+        $replace = null;
+
+        switch ($operator_value) {
+          case '?':
+            if ($shorthand) {
+              $replace = " {$operator_value}";
+            } else {
+              $replace = " {$operator_value} ";
+            }
+            break;
+
+          case ':':
+            if ($shorthand) {
+              $replace = "{$operator_value} ";
+            } else {
+              $replace = " {$operator_value} ";
+            }
+            break;
+        }
+
+        if ($replace !== null) {
+          $this->raiseLintAtToken(
+            $operator,
+            pht(
+              'Convention: ternary operators should be '.
+              'surrounded by whitespace.'),
+            $replace);
+        }
+      }
+    }
+  }
+
+}
diff --git a/src/lint/linter/xhpast/rules/__tests__/ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase.php b/src/lint/linter/xhpast/rules/__tests__/ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase.php
new file mode 100644
--- /dev/null
+++ b/src/lint/linter/xhpast/rules/__tests__/ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase.php
@@ -0,0 +1,11 @@
+<?php
+
+final class ArcanistTernaryExpressionSpacingXHPASTLinterRuleTestCase
+  extends ArcanistXHPASTLinterRuleTestCase {
+
+  public function testLinter() {
+    $this->executeTestsInDirectory(
+      dirname(__FILE__).'/ternary-expression-spacing/');
+  }
+
+}
diff --git a/src/lint/linter/xhpast/rules/__tests__/ternary-expression-spacing/ternary-expression-spacing.lint-test b/src/lint/linter/xhpast/rules/__tests__/ternary-expression-spacing/ternary-expression-spacing.lint-test
new file mode 100644
--- /dev/null
+++ b/src/lint/linter/xhpast/rules/__tests__/ternary-expression-spacing/ternary-expression-spacing.lint-test
@@ -0,0 +1,20 @@
+<?php
+
+$x?$y:$z;
+$x?:$y;
+~~~~~~~~~~
+warning:3:3
+warning:3:6
+warning:4:3
+warning:4:4
+~~~~~~~~~~
+<?php
+
+$x ? $y : $z;
+$x ?: $y;
+~~~~~~~~~~
+{
+  "config": {
+    "xhpast.php-version": "5.4.0"
+  }
+}