diff --git a/src/core/fullscreen_ui.cpp b/src/core/fullscreen_ui.cpp
index 5541837ee..b27450b5c 100644
--- a/src/core/fullscreen_ui.cpp
+++ b/src/core/fullscreen_ui.cpp
@@ -488,10 +488,11 @@ static constexpr const std::array s_ps_button_mapping{
 static constexpr std::array s_theme_names = {
   FSUI_NSTR("Automatic"),  FSUI_NSTR("Dark"),       FSUI_NSTR("Light"),
   FSUI_NSTR("AMOLED"),     FSUI_NSTR("Cobalt Sky"), FSUI_NSTR("Grey Matter"),
-  FSUI_NSTR("Pinky Pals"), FSUI_NSTR("Dark Ruby"),  FSUI_NSTR("Purple Rain")};
+  FSUI_NSTR("Green Giant"), FSUI_NSTR("Pinky Pals"), FSUI_NSTR("Dark Ruby"),
+  FSUI_NSTR("Purple Rain")};
 
-static constexpr std::array s_theme_values = {"",           "Dark",      "Light",    "AMOLED",    "CobaltSky",
-                                              "GreyMatter", "PinkyPals", "DarkRuby", "PurpleRain"};
+static constexpr std::array s_theme_values = {"",           "Dark",       "Light",     "AMOLED",   "CobaltSky",
+                                              "GreyMatter", "GreenGiant", "PinkyPals", "DarkRuby", "PurpleRain"};
 
 //////////////////////////////////////////////////////////////////////////
 // State
diff --git a/src/duckstation-qt/interfacesettingswidget.cpp b/src/duckstation-qt/interfacesettingswidget.cpp
index 0f6bbf888..e7c13b9cd 100644
--- a/src/duckstation-qt/interfacesettingswidget.cpp
+++ b/src/duckstation-qt/interfacesettingswidget.cpp
@@ -20,6 +20,7 @@ const char* InterfaceSettingsWidget::THEME_NAMES[] = {
   QT_TRANSLATE_NOOP("MainWindow", "AMOLED"),
   QT_TRANSLATE_NOOP("MainWindow", "Cobalt Sky"),
   QT_TRANSLATE_NOOP("MainWindow", "Grey Matter"),
+  QT_TRANSLATE_NOOP("MainWindow", "Green Giant"),
   QT_TRANSLATE_NOOP("MainWindow", "Pinky Pals"),
   QT_TRANSLATE_NOOP("MainWindow", "Dark Ruby"),
   QT_TRANSLATE_NOOP("MainWindow", "Purple Rain"),
@@ -38,6 +39,7 @@ const char* InterfaceSettingsWidget::THEME_VALUES[] = {
   "AMOLED",
   "cobaltsky",
   "greymatter",
+  "greengiant",
   "pinkypals",
   "darkruby",
   "purplerain",
diff --git a/src/duckstation-qt/qtthemes.cpp b/src/duckstation-qt/qtthemes.cpp
index d08507df1..3b188fc9e 100644
--- a/src/duckstation-qt/qtthemes.cpp
+++ b/src/duckstation-qt/qtthemes.cpp
@@ -202,6 +202,40 @@ void QtHost::SetStyleFromSettings()
     qApp->setPalette(darkPalette);
     qApp->setStyleSheet(QString());
   }
+	else if (theme == "greengiant")
+	{
+		// Custom palette by RedDevilus, Tame (Light/Washed out) Green as main color and Grayish Blue as complimentary.
+		// Alternative white theme.
+		qApp->setStyle(QStyleFactory::create("Fusion"));
+
+		const QColor black(25, 25, 25);
+		const QColor gray(111, 111, 111);
+		const QColor limerick(176, 196, 0);
+		const QColor brown(135, 100, 50);
+		const QColor pear(213, 222, 46);
+
+		QPalette greenGiantPalette;
+		greenGiantPalette.setColor(QPalette::Window, pear);
+		greenGiantPalette.setColor(QPalette::WindowText, black);
+		greenGiantPalette.setColor(QPalette::Base, limerick);
+		greenGiantPalette.setColor(QPalette::AlternateBase, brown.lighter());
+		greenGiantPalette.setColor(QPalette::ToolTipBase, brown);
+		greenGiantPalette.setColor(QPalette::ToolTipText, Qt::white);
+		greenGiantPalette.setColor(QPalette::Text, black);
+		greenGiantPalette.setColor(QPalette::Button, brown.lighter());
+		greenGiantPalette.setColor(QPalette::ButtonText, black.lighter());
+		greenGiantPalette.setColor(QPalette::Link, brown.lighter());
+		greenGiantPalette.setColor(QPalette::Highlight, brown);
+		greenGiantPalette.setColor(QPalette::HighlightedText, Qt::white);
+
+		greenGiantPalette.setColor(QPalette::Disabled, QPalette::ButtonText, gray);
+		greenGiantPalette.setColor(QPalette::Disabled, QPalette::WindowText, gray.darker());
+		greenGiantPalette.setColor(QPalette::Disabled, QPalette::Text, gray.darker());
+		greenGiantPalette.setColor(QPalette::Disabled, QPalette::Light, gray);
+
+		qApp->setPalette(greenGiantPalette);
+		qApp->setStyleSheet(QString());
+	}
   else if (theme == "pinkypals")
   {
     qApp->setStyle(QStyleFactory::create("Fusion"));
@@ -371,6 +405,8 @@ const char* Host::GetDefaultFullscreenUITheme()
     return "CobaltSky";
   else if (theme == "greymatter")
     return "GreyMatter";
+  else if (theme == "greengiant")
+    return "GreenGiant";
   else if (theme == "pinkypals")
     return "PinkyPals";
   else if (theme == "purplerain")
diff --git a/src/util/imgui_fullscreen.cpp b/src/util/imgui_fullscreen.cpp
index 0bceff739..ddaf2b18e 100644
--- a/src/util/imgui_fullscreen.cpp
+++ b/src/util/imgui_fullscreen.cpp
@@ -3620,6 +3620,28 @@ void ImGuiFullscreen::SetTheme(std::string_view theme)
     UIStyle.ToastTextColor = HEX_TO_IMVEC4(0xffffff, 0xff);
     UIStyle.ShadowColor = IM_COL32(100, 100, 100, 50);
   }
+	else if (theme == "GreenGiant")
+	{
+		UIStyle.BackgroundColor = HEX_TO_IMVEC4(0xB0C400, 0xff);
+		UIStyle.BackgroundTextColor = HEX_TO_IMVEC4(0x000000, 0xff);
+		UIStyle.BackgroundLineColor = HEX_TO_IMVEC4(0xf0f0f0, 0xff);
+		UIStyle.BackgroundHighlight = HEX_TO_IMVEC4(0x876433, 0xff);
+		UIStyle.PopupBackgroundColor = HEX_TO_IMVEC4(0xB0C400, 0xf2);
+		UIStyle.PrimaryColor = HEX_TO_IMVEC4(0xD5DE2E, 0xff);
+		UIStyle.PrimaryLightColor = HEX_TO_IMVEC4(0x795A2D, 0xff);
+		UIStyle.PrimaryDarkColor = HEX_TO_IMVEC4(0x523213, 0xff);
+		UIStyle.PrimaryTextColor = HEX_TO_IMVEC4(0x000000, 0xff);
+		UIStyle.DisabledColor = HEX_TO_IMVEC4(0x878269, 0xff);
+		UIStyle.TextHighlightColor = HEX_TO_IMVEC4(0xffffff, 0xff);
+		UIStyle.PrimaryLineColor = HEX_TO_IMVEC4(0xffffff, 0xff);
+		UIStyle.SecondaryColor = HEX_TO_IMVEC4(0x523213, 0xff);
+		UIStyle.SecondaryStrongColor = HEX_TO_IMVEC4(0x523213, 0xff);
+		UIStyle.SecondaryWeakColor = HEX_TO_IMVEC4(0x523213, 0xff);
+		UIStyle.SecondaryTextColor = HEX_TO_IMVEC4(0x000000, 0xff);
+    UIStyle.ToastBackgroundColor = HEX_TO_IMVEC4(0xD5DE2E, 0xff);
+    UIStyle.ToastTextColor = HEX_TO_IMVEC4(0x000000, 0xff);
+    UIStyle.ShadowColor = IM_COL32(100, 100, 100, 50);
+	}
   else if (theme == "DarkRuby")
   {
     UIStyle.BackgroundColor = HEX_TO_IMVEC4(0x1b1b1b, 0xff);