diff --git a/src/Lookup/EEPROMLookup.php b/src/Lookup/EEPROMLookup.php
index 29d7c78..9a66613 100644
--- a/src/Lookup/EEPROMLookup.php
+++ b/src/Lookup/EEPROMLookup.php
@@ -15,10 +15,11 @@ final class EEPROMLookup implements \Uiharu\ILookup {
     ) {}
 
     public function match(Url $url): bool {
+        $urlHost = strtolower($url->getHost());
         return $url->getScheme() === $this->protocol || (
             $url->isWeb() && (
-                in_array($url->getHost(), $this->shortDomains) || (
-                    $url->getHost() === $this->apiDomain && str_starts_with($url->getPath(), '/uploads')
+                in_array($urlHost, $this->shortDomains) || (
+                    $urlHost === $this->apiDomain && str_starts_with($url->getPath(), '/uploads')
                 )
             )
         );
diff --git a/src/Lookup/NicoNicoLookup.php b/src/Lookup/NicoNicoLookup.php
index 34ee137..f7d69f5 100644
--- a/src/Lookup/NicoNicoLookup.php
+++ b/src/Lookup/NicoNicoLookup.php
@@ -28,10 +28,12 @@ final class NicoNicoLookup implements \Uiharu\ILookup {
         if(!$url->isWeb())
             return false;
 
-        if(self::isShortDomain($url->getHost()))
+        $urlHost = strtolower($url->getHost());
+
+        if(self::isShortDomain($urlHost))
             return true;
 
-        if(self::isLongDomain($url->getHost()) && str_starts_with($url->getPath(), '/watch/sm'))
+        if(self::isLongDomain($urlHost) && str_starts_with($url->getPath(), '/watch/sm'))
             return true;
 
         return false;
diff --git a/src/Lookup/TwitterLookup.php b/src/Lookup/TwitterLookup.php
index 1acae8f..a139ddb 100644
--- a/src/Lookup/TwitterLookup.php
+++ b/src/Lookup/TwitterLookup.php
@@ -14,7 +14,7 @@ final class TwitterLookup implements \Uiharu\ILookup {
     ];
 
     public function match(Url $url): bool {
-        if(!$url->isWeb() || !in_array($url->getHost(), self::TWITTER_DOMAINS))
+        if(!$url->isWeb() || !in_array(strtolower($url->getHost()), self::TWITTER_DOMAINS))
             return false;
 
         return preg_match('#^/@?(?:[A-Za-z0-9_]{1,20})/status(?:es)?/([0-9]+)/?$#', $url->getPath())
diff --git a/src/Lookup/YouTubeLookup.php b/src/Lookup/YouTubeLookup.php
index 78c8f59..f005a3f 100644
--- a/src/Lookup/YouTubeLookup.php
+++ b/src/Lookup/YouTubeLookup.php
@@ -38,7 +38,7 @@ final class YouTubeLookup implements \Uiharu\ILookup {
         if(!$url->isWeb())
             return false;
 
-        $urlHost = $url->getHost();
+        $urlHost = strtolower($url->getHost());
         if(self::isShortDomain($urlHost))
             return true;