diff --git a/Parser/AbstractParser.php b/Parser/AbstractParser.php
index 7c4945af23..188c22334e 100644
--- a/Parser/AbstractParser.php
+++ b/Parser/AbstractParser.php
@@ -351,6 +351,7 @@ protected function hasDesktopFragment(): bool
             'CE-HTML',
             ' Mozilla/|Andr[o0]id|Tablet|Mobile|iPhone|Windows Phone|ricoh|OculusBrowser',
             'PicoBrowser|Lenovo|compatible; MSIE|Trident/|Tesla/|XBOX|FBMD/|ARM; ?([^)]+)',
+            'Steam',
         ]);
 
         return
diff --git a/Parser/Device/AbstractDeviceParser.php b/Parser/Device/AbstractDeviceParser.php
index 9b7c0ba835..c69a9e3e9f 100644
--- a/Parser/Device/AbstractDeviceParser.php
+++ b/Parser/Device/AbstractDeviceParser.php
@@ -1998,6 +1998,7 @@ abstract class AbstractDeviceParser extends AbstractParser
         'VAL' => 'VALEM',
         'VA2' => 'VALE',
         'VAT' => 'VALTECH',
+        'VLV' => 'Valve Corporation',
         'VAN' => 'VANGUARD',
         'VAW' => 'VANWIN',
         'VB'  => 'VC',
diff --git a/Parser/OperatingSystem.php b/Parser/OperatingSystem.php
index 244ec41f94..85639742be 100644
--- a/Parser/OperatingSystem.php
+++ b/Parser/OperatingSystem.php
@@ -210,6 +210,7 @@ class OperatingSystem extends AbstractParser
         'SMA' => 'Smartisan OS',
         'SOS' => 'Solaris',
         'SBL' => 'Star-Blade OS',
+        'STM' => 'SteamOS',
         'SYL' => 'Syllable',
         'SYM' => 'Symbian',
         'SYS' => 'Symbian OS',
@@ -287,7 +288,7 @@ class OperatingSystem extends AbstractParser
             'KOB', 'FRT',
         ],
         'Mac'                   => ['MAC'],
-        'Mobile Gaming Console' => ['PSP', 'NDS', 'XBX'],
+        'Mobile Gaming Console' => ['PSP', 'NDS', 'XBX', 'STM'],
         'OpenHarmony'           => ['OHS', 'HNX'],
         'OpenVMS'               => ['OVS'],
         'Real-time OS'          => ['MTK', 'TDX', 'MRE', 'JME', 'REX', 'RXT', 'KOL', 'MOS', 'NTX'],
diff --git a/Tests/Parser/Client/fixtures/browser.yml b/Tests/Parser/Client/fixtures/browser.yml
index cf0ff51520..3c2104451d 100644
--- a/Tests/Parser/Client/fixtures/browser.yml
+++ b/Tests/Parser/Client/fixtures/browser.yml
@@ -11703,3 +11703,12 @@
     engine: Blink
     engine_version: ""
     family: Chrome
+-
+  user_agent: Mozilla/5.0 (X11; Linux x86_64; Valve Steam GameOverlay; ) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36
+  client:
+    type: browser
+    name: Steam In-Game Overlay
+    version: ""
+    engine: Blink
+    engine_version: 85.0.4183.102
+    family: Chrome
diff --git a/Tests/Parser/fixtures/oss.yml b/Tests/Parser/fixtures/oss.yml
index 73dba4e4b9..d527dc7d57 100644
--- a/Tests/Parser/fixtures/oss.yml
+++ b/Tests/Parser/fixtures/oss.yml
@@ -7226,3 +7226,11 @@
     version: "7.0"
     platform: ""
     family: GNU/Linux
+-
+  user_agent: Mozilla/5.0 (X11; Linux x86_64; Valve Steam GameOverlay; ) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36
+  os:
+    name: SteamOS
+    short_name: STM
+    version: ""
+    platform: x64
+    family: Mobile Gaming Console
diff --git a/Tests/fixtures/console.yml b/Tests/fixtures/console.yml
index 350aa0a1e8..5e3d36da98 100644
--- a/Tests/fixtures/console.yml
+++ b/Tests/fixtures/console.yml
@@ -846,3 +846,39 @@
     model: Switch Lite
   os_family: Gaming Console
   browser_family: NetFront
+-
+  user_agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36 SteamDeck
+  os:
+    name: SteamOS
+    version: ""
+    platform: x64
+  client:
+    type: browser
+    name: Chrome
+    version: 131.0.0.0
+    engine: Blink
+    engine_version: 131.0.0.0
+  device:
+    type: console
+    brand: Valve Corporation
+    model: Steam Deck
+  os_family: Mobile Gaming Console
+  browser_family: Chrome
+-
+  user_agent: Mozilla/5.0 (X11; Linux x86_64; Valve Steam GameOverlay; ) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.102 Safari/537.36
+  os:
+    name: SteamOS
+    version: ""
+    platform: x64
+  client:
+    type: browser
+    name: Steam In-Game Overlay
+    version: ""
+    engine: Blink
+    engine_version: 85.0.4183.102
+  device:
+    type: console
+    brand: Valve Corporation
+    model: ""
+  os_family: Mobile Gaming Console
+  browser_family: Chrome
diff --git a/regexes/client/browsers.yml b/regexes/client/browsers.yml
index 8858efe53e..c03bb2b5d6 100644
--- a/regexes/client/browsers.yml
+++ b/regexes/client/browsers.yml
@@ -1455,7 +1455,7 @@
   version: '$1'
 
 # Steam (https://www.valvesoftware.com/)
-- regex: 'Valve Steam GameOverlay/(?:(\d+[.\d]+))?'
+- regex: 'Valve Steam GameOverlay(?:/(\d+[.\d]+))?'
   name: 'Steam In-Game Overlay'
   version: '$1'
 
diff --git a/regexes/device/consoles.yml b/regexes/device/consoles.yml
index fb5a848f29..9b3b344da4 100644
--- a/regexes/device/consoles.yml
+++ b/regexes/device/consoles.yml
@@ -82,3 +82,11 @@ Retroid Pocket:
       model: '4 Pro'
     - regex: 'Pocket ([235])'
       model: '$1'
+
+# Valve Corporation (https://www.steamdeck.com/en/)
+Valve Corporation:
+  regex: 'Steam'
+  device: 'console'
+  models:
+    - regex: 'SteamDeck'
+      model: 'Steam Deck'
diff --git a/regexes/oss.yml b/regexes/oss.yml
index c67fb1bb72..375ac62ca0 100644
--- a/regexes/oss.yml
+++ b/regexes/oss.yml
@@ -5,6 +5,13 @@
 # @license http://www.gnu.org/licenses/lgpl.html LGPL v3 or later
 ###############
 
+##########
+# SteamOS (https://store.steampowered.com/steamos)
+##########
+- regex: 'Steam'
+  name: 'SteamOS'
+  version: ''
+
 ##########
 # FortiOS (https://www.fortinet.com/products/fortigate/fortios)
 ##########