diff --git a/src/Application.php b/src/Application.php
index 1b3f72b..45a0a0a 100644
--- a/src/Application.php
+++ b/src/Application.php
@@ -107,7 +107,12 @@ public function run(): int
             return 2;
         }
 
-        $reporter = $this->createReporter($options['report'], $options['colors']);
+        $reporter = $this->createReporter(
+            $options['report'],
+            $options['colors'],
+            $options['perf']
+        );
+
         $this->write($reporter->generate($report));
 
         return (int) $report->hasViolations();
@@ -144,6 +149,7 @@ private function resolveOverridePaths(array $paths): array
      *     quiet: bool,
      *     paths: list<string>,
      *     diff: string|null,
+     *     perf: bool,
      * }
      */
     private function parseArgv(): array
@@ -157,6 +163,7 @@ private function parseArgv(): array
             'quiet' => false,
             'paths' => [],
             'diff' => null,
+            'perf' => false,
         ];
 
         $args = array_slice($this->argv, 1); // skip script name
@@ -235,6 +242,12 @@ private function parseArgv(): array
                 continue;
             }
 
+            if ($arg === '--perf') {
+                $result['perf'] = true;
+                $i++;
+                continue;
+            }
+
             // Anything else is a path to scan.
             if (!str_starts_with($arg, '-')) {
                 $result['paths'][] = $arg;
@@ -302,12 +315,12 @@ private function loadConfig(string $configPath): ConfigData
         return $parser->parseFile($configPath);
     }
 
-    private function createReporter(string $format, bool $colors): ReporterInterface
+    private function createReporter(string $format, bool $colors, bool $perf): ReporterInterface
     {
         return match ($format) {
             'checkstyle' => new CheckstyleReporter(),
             'json' => new JsonReporter(),
-            default => new ConsoleReporter($colors),
+            default => new ConsoleReporter($colors, $perf),
         };
     }
 
diff --git a/src/Report/Report.php b/src/Report/Report.php
index 4723809..37ccbe5 100644
--- a/src/Report/Report.php
+++ b/src/Report/Report.php
@@ -11,6 +11,11 @@ final class Report
 
     private int $filesScanned = 0;
 
+    private float $totalTime = 0.0;
+
+    /** @var array<string, float> */
+    private array $sniffTimes = [];
+
     public function addFileReport(FileReport $fileReport): void
     {
         $this->fileReports[$fileReport->filePath] = $fileReport;
@@ -79,4 +84,29 @@ public function getAllViolations(): array
 
         return $all;
     }
+
+    public function setTotalTime(float $time): void
+    {
+        $this->totalTime = $time;
+    }
+
+    public function addSniffTime(string $sniffClass, float $time): void
+    {
+        if (!isset($this->sniffTimes[$sniffClass])) {
+            $this->sniffTimes[$sniffClass] = 0.0;
+        }
+
+        $this->sniffTimes[$sniffClass] += $time;
+    }
+
+    public function getTotalTime(): float
+    {
+        return $this->totalTime;
+    }
+
+    /** @return array<string, float> */
+    public function getSniffTimes(): array
+    {
+        return $this->sniffTimes;
+    }
 }
diff --git a/src/Report/Reporter/CheckstyleReporter.php b/src/Report/Reporter/CheckstyleReporter.php
index bcba3f9..6076f2c 100644
--- a/src/Report/Reporter/CheckstyleReporter.php
+++ b/src/Report/Reporter/CheckstyleReporter.php
@@ -17,6 +17,11 @@ public function generate(Report $report): string
         $root->setAttribute('version', '3.0');
         $dom->appendChild($root);
 
+        $comment = $dom->createComment(
+            sprintf(' total runtime: %.3fs ', $report->getTotalTime())
+        );
+        $root->appendChild($comment);
+
         foreach ($report->getFileReports() as $fileReport) {
             if (!$fileReport->hasViolations()) {
                 continue;
diff --git a/src/Report/Reporter/ConsoleReporter.php b/src/Report/Reporter/ConsoleReporter.php
index b91d81e..6a81eb1 100644
--- a/src/Report/Reporter/ConsoleReporter.php
+++ b/src/Report/Reporter/ConsoleReporter.php
@@ -10,10 +10,12 @@
 final class ConsoleReporter implements ReporterInterface
 {
     private bool $useColors;
+    private bool $showPerformance;
 
-    public function __construct(bool $useColors = true)
+    public function __construct(bool $useColors = true, bool $showPerformance = false)
     {
         $this->useColors = $useColors;
+        $this->showPerformance = $showPerformance;
     }
 
     public function generate(Report $report): string
@@ -45,6 +47,11 @@ public function generate(Report $report): string
         $output .= PHP_EOL;
         $output .= $this->buildSummary($report) . PHP_EOL;
 
+        if ($this->showPerformance) {
+            $output .= PHP_EOL;
+            $output .= $this->buildPerformance($report) . PHP_EOL;
+        }
+
         return $output;
     }
 
@@ -54,6 +61,9 @@ private function buildSummary(Report $report): string
         $errors = $report->getTotalErrors();
         $warnings = $report->getTotalWarnings();
         $total = $report->getTotalViolations();
+        $time = $report->getTotalTime();
+
+        $timeLine = sprintf('Total runtime: %.3fs', $time);
 
         if ($total === 0) {
             return $this->green(
@@ -61,7 +71,7 @@ private function buildSummary(Report $report): string
                     'OK -- %d file(s) scanned, no violations found.',
                     $files,
                 )
-            );
+            ) . PHP_EOL . $this->dim($timeLine);
         }
 
         return $this->red(
@@ -72,7 +82,41 @@ private function buildSummary(Report $report): string
                 $warnings,
                 count($report->getFileReports()),
             )
-        );
+        ) . PHP_EOL . $this->dim($timeLine);
+    }
+
+    private function buildPerformance(Report $report): string
+    {
+        $totalTime = $report->getTotalTime();
+        $sniffTimes = $report->getSniffTimes();
+
+        if ($totalTime <= 0.0 || $sniffTimes === []) {
+            return $this->dim('No performance data available.');
+        }
+
+        // Sort slowest first
+        arsort($sniffTimes);
+
+        $output = $this->bold('PERFORMANCE') . PHP_EOL;
+        $output .= str_repeat('-', 40) . PHP_EOL;
+
+        $output .= sprintf(
+            ' Total runtime: %.3fs',
+            $totalTime
+        ) . PHP_EOL . PHP_EOL;
+
+        foreach ($sniffTimes as $sniff => $time) {
+            $percent = ($time / $totalTime) * 100;
+
+            $output .= sprintf(
+                ' %-40s %6.3fs (%5.1f%%)',
+                $sniff,
+                $time,
+                $percent,
+            ) . PHP_EOL;
+        }
+
+        return $output;
     }
 
     private function formatSeverity(Severity $severity): string
diff --git a/src/Report/Reporter/JsonReporter.php b/src/Report/Reporter/JsonReporter.php
index e413167..0e52b0f 100644
--- a/src/Report/Reporter/JsonReporter.php
+++ b/src/Report/Reporter/JsonReporter.php
@@ -18,6 +18,9 @@ public function generate(Report $report): string
                 'warnings' => $report->getTotalWarnings(),
             ],
             'files' => [],
+            'performance' => [
+                'total_runtime_seconds' => $report->getTotalTime(),
+            ],
         ];
 
         foreach ($report->getFileReports() as $fileReport) {
diff --git a/src/Runner/SniffRunner.php b/src/Runner/SniffRunner.php
index 902ae79..73fdfbc 100644
--- a/src/Runner/SniffRunner.php
+++ b/src/Runner/SniffRunner.php
@@ -30,6 +30,8 @@ public function __construct(?ProgressInterface $progress = null)
      */
     public function run(ConfigData $config, ?array $overridePaths = null, ?array $diffLines = null): Report
     {
+        $startTime = microtime(true);
+
         $sniffs = $this->instantiateSniffs($config->getSniffs());
 
         $matcher = new PathMatcher($config->getExcludePatterns());
@@ -43,10 +45,10 @@ public function run(ConfigData $config, ?array $overridePaths = null, ?array $di
             $files = $this->filterByDiff($files, array_keys($diffLines));
         }
 
+        $report = new Report();
         $preprocessor = new EntityPreprocessor();
-        $processor = new XmlFileProcessor($sniffs, $preprocessor);
+        $processor = new XmlFileProcessor($sniffs, $preprocessor, $report);
 
-        $report = new Report();
         $total = count($files);
 
         $this->progress->start($total);
@@ -54,8 +56,15 @@ public function run(ConfigData $config, ?array $overridePaths = null, ?array $di
         foreach ($files as $index => $file) {
             $report->incrementFilesScanned();
 
-            $changedLines = $diffLines !== null ? $this->getChangedLinesForFile($file, $diffLines) : [];
-            $fileReport = $processor->processFile($file, $changedLines, $this->makeRelative($file));
+            $changedLines = $diffLines !== null
+                ? $this->getChangedLinesForFile($file, $diffLines)
+                : [];
+
+            $fileReport = $processor->processFile(
+                $file,
+                $changedLines,
+                $this->makeRelative($file),
+            );
 
             $violationCount = $fileReport->getViolationCount();
 
@@ -68,6 +77,8 @@ public function run(ConfigData $config, ?array $overridePaths = null, ?array $di
 
         $this->progress->finish();
 
+        $report->setTotalTime(microtime(true) - $startTime);
+
         return $report;
     }
 
@@ -150,8 +161,10 @@ private function makeRelative(string $absolutePath): string
         if ($cwd === false) {
             return $absolutePath; // @codeCoverageIgnore
         }
+
         $prefix = rtrim(str_replace('\\', '/', $cwd), '/') . '/';
         $normalized = str_replace('\\', '/', $absolutePath);
+
         if (str_starts_with($normalized, $prefix)) {
             return substr($normalized, strlen($prefix));
         }
diff --git a/src/Runner/XmlFileProcessor.php b/src/Runner/XmlFileProcessor.php
index 8c436f4..2ab2f29 100644
--- a/src/Runner/XmlFileProcessor.php
+++ b/src/Runner/XmlFileProcessor.php
@@ -5,6 +5,7 @@
 namespace DocbookCS\Runner;
 
 use DocbookCS\Report\FileReport;
+use DocbookCS\Report\Report;
 use DocbookCS\Report\Severity;
 use DocbookCS\Report\Violation;
 use DocbookCS\Sniff\SniffInterface;
@@ -16,16 +17,17 @@ final class XmlFileProcessor
 
     private EntityPreprocessor $preprocessor;
 
-    /**
-     * @param list<SniffInterface> $sniffs
-     * @param EntityPreprocessor|null $preprocessor
-     */
+    private Report $report;
+
+    /** @param list<SniffInterface> $sniffs */
     public function __construct(
         array $sniffs,
         ?EntityPreprocessor $preprocessor = null,
+        ?Report $report = null,
     ) {
         $this->sniffs = $sniffs;
         $this->preprocessor = $preprocessor ?? new EntityPreprocessor();
+        $this->report = $report ?? new Report();
     }
 
     /** @param list<int> $changedLines */
@@ -76,9 +78,13 @@ private function processContent(
 
         $violations = [];
         foreach ($this->sniffs as $sniff) {
+            $start = microtime(true);
+
             foreach ($sniff->process($document, $content, $filePath) as $violation) {
                 $violations[] = $violation;
             }
+
+            $this->report->addSniffTime($sniff->getCode(), microtime(true) - $start);
         }
 
         if ($changedLines !== []) {
diff --git a/tests/Unit/ApplicationTest.php b/tests/Unit/ApplicationTest.php
index fd58b6c..22c8664 100644
--- a/tests/Unit/ApplicationTest.php
+++ b/tests/Unit/ApplicationTest.php
@@ -424,4 +424,47 @@ public function itSuppressesProgressForStructuredReportFormats(): void
             self::assertSame('', $this->readStream($stderr), "stderr should be empty for --report={$format}");
         }
     }
+
+    #[Test]
+    public function itShowsPerformanceWhenPerfFlagIsEnabled(): void
+    {
+        $app = new Application(
+            [
+                'docbook-cs',
+                '--config=' . self::VALID_CONFIG,
+                '--perf',
+                self::SCAN_FILE,
+            ],
+            $this->stdout,
+            $this->stderr,
+        );
+
+        $exitCode = $app->run();
+
+        self::assertNotSame(2, $exitCode);
+
+        $output = $this->readStream($this->stdout);
+
+        self::assertStringContainsString('PERFORMANCE', $output);
+    }
+
+    #[Test]
+    public function itDoesNotShowPerformanceByDefault(): void
+    {
+        $app = new Application(
+            [
+                'docbook-cs',
+                '--config=' . self::VALID_CONFIG,
+                self::SCAN_FILE,
+            ],
+            $this->stdout,
+            $this->stderr,
+        );
+
+        $app->run();
+
+        $output = $this->readStream($this->stdout);
+
+        self::assertStringNotContainsString('PERFORMANCE', $output);
+    }
 }
diff --git a/tests/Unit/Report/Reporter/ConsoleReporterTest.php b/tests/Unit/Report/Reporter/ConsoleReporterTest.php
index 4e65736..1dd96b8 100644
--- a/tests/Unit/Report/Reporter/ConsoleReporterTest.php
+++ b/tests/Unit/Report/Reporter/ConsoleReporterTest.php
@@ -360,4 +360,85 @@ public function itSeparatesFieldsWithPipes(): void
         self::assertNotEmpty($violationLine);
         self::assertSame(3, substr_count($violationLine, '|'));
     }
+
+    #[Test]
+    public function itShowsNoPerformanceDataWhenEmpty(): void
+    {
+        $reporter = new ConsoleReporter(useColors: false, showPerformance: true);
+
+        $report = new Report();
+        $report->incrementFilesScanned();
+
+        $output = $reporter->generate($report);
+
+        self::assertStringContainsString('No performance data available.', $output);
+    }
+
+    #[Test]
+    public function itShowsPerformanceSectionWithHeader(): void
+    {
+        $reporter = new ConsoleReporter(useColors: false, showPerformance: true);
+
+        $report = new Report();
+        $report->incrementFilesScanned();
+
+        $report->setTotalTime(2.0);
+        $report->addSniffTime('SniffA', 1.0);
+
+        $output = $reporter->generate($report);
+
+        self::assertStringContainsString('PERFORMANCE', $output);
+        self::assertStringContainsString('Total runtime: 2.000s', $output);
+    }
+
+    #[Test]
+    public function itSortsSniffTimesBySlowestFirst(): void
+    {
+        $reporter = new ConsoleReporter(useColors: false, showPerformance: true);
+
+        $report = new Report();
+        $report->setTotalTime(3.0);
+
+        $report->addSniffTime('FastSniff', 0.5);
+        $report->addSniffTime('SlowSniff', 2.0);
+        $report->addSniffTime('MediumSniff', 1.0);
+
+        $output = $reporter->generate($report);
+
+        $slowPos = strpos($output, 'SlowSniff');
+        $mediumPos = strpos($output, 'MediumSniff');
+        $fastPos = strpos($output, 'FastSniff');
+
+        self::assertTrue($slowPos < $mediumPos);
+        self::assertTrue($mediumPos < $fastPos);
+    }
+
+    #[Test]
+    public function itDisplaysTimeAndPercentagePerSniff(): void
+    {
+        $reporter = new ConsoleReporter(useColors: false, showPerformance: true);
+
+        $report = new Report();
+        $report->setTotalTime(2.0);
+
+        $report->addSniffTime('SniffA', 1.0); // 50%
+
+        $output = $reporter->generate($report);
+
+        self::assertStringContainsString('1.000s ( 50.0%)', $output);
+    }
+
+    #[Test]
+    public function itDoesNotShowPerformanceWhenDisabled(): void
+    {
+        $reporter = new ConsoleReporter(useColors: false, showPerformance: false);
+
+        $report = new Report();
+        $report->setTotalTime(2.0);
+        $report->addSniffTime('SniffA', 1.0);
+
+        $output = $reporter->generate($report);
+
+        self::assertStringNotContainsString('PERFORMANCE', $output);
+    }
 }
diff --git a/tests/Unit/Runner/XmlFileProcessorTest.php b/tests/Unit/Runner/XmlFileProcessorTest.php
index a1fc762..f35e3c4 100644
--- a/tests/Unit/Runner/XmlFileProcessorTest.php
+++ b/tests/Unit/Runner/XmlFileProcessorTest.php
@@ -5,6 +5,7 @@
 namespace DocbookCS\Tests\Unit\Runner;
 
 use DocbookCS\Report\FileReport;
+use DocbookCS\Report\Report;
 use DocbookCS\Report\Severity;
 use DocbookCS\Report\Violation;
 use DocbookCS\Runner\XmlFileProcessor;
@@ -18,6 +19,7 @@
 #[CoversClass(FileReport::class)]
 #[CoversClass(Violation::class)]
 #[CoversClass(XmlFileProcessor::class)]
+#[CoversClass(Report::class)]
 final class XmlFileProcessorTest extends TestCase
 {
     #[Test]