diff --git a/platforms/desktop-shared/emu.cpp b/platforms/desktop-shared/emu.cpp
index 54fdac72..cd2a1dc6 100644
--- a/platforms/desktop-shared/emu.cpp
+++ b/platforms/desktop-shared/emu.cpp
@@ -383,7 +383,10 @@ void emu_set_overscan(int overscan)
             gearsystem->GetVideo()->SetOverscan(Video::OverscanTopBottom);
             break;
         case 2:
-            gearsystem->GetVideo()->SetOverscan(Video::OverscanFull);
+            gearsystem->GetVideo()->SetOverscan(Video::OverscanFull284);
+            break;
+        case 3:
+            gearsystem->GetVideo()->SetOverscan(Video::OverscanFull320);
             break;
         default:
             gearsystem->GetVideo()->SetOverscan(Video::OverscanDisabled);
diff --git a/platforms/desktop-shared/gui.cpp b/platforms/desktop-shared/gui.cpp
index e0595323..a3d256f1 100644
--- a/platforms/desktop-shared/gui.cpp
+++ b/platforms/desktop-shared/gui.cpp
@@ -115,7 +115,7 @@ void gui_init(void)
     emu_enable_bootrom_sms(config_emulator.sms_bootrom);
     emu_enable_bootrom_gg(config_emulator.gg_bootrom);
     emu_set_media_slot(config_emulator.media);
-    emu_set_overscan(config_debug.debug ? false : config_video.overscan);
+    emu_set_overscan(config_debug.debug ? 0 : config_video.overscan);
     emu_disable_ym2413(config_audio.ym2413 == 1);
 }
 
@@ -650,10 +650,10 @@ static void main_menu(void)
 
             if (ImGui::BeginMenu("Overscan"))
             {
-                ImGui::PushItemWidth(120.0f);
-                if (ImGui::Combo("##overscan", &config_video.overscan, "Disabled\0Top+Bottom\0Full\0\0"))
+                ImGui::PushItemWidth(170.0f);
+                if (ImGui::Combo("##overscan", &config_video.overscan, "Disabled\0Top+Bottom\0Full (284 width)\0Full (320 width)\0\0"))
                 {
-                    emu_set_overscan(config_debug.debug ? false : config_video.overscan);
+                    emu_set_overscan(config_debug.debug ? 0 : config_video.overscan);
                 }
                 ImGui::PopItemWidth();
                 ImGui::EndMenu();
@@ -849,7 +849,7 @@ static void main_menu(void)
 
             if (ImGui::MenuItem("Enable", "", &config_debug.debug))
             {
-                emu_set_overscan(config_debug.debug ? false : config_video.overscan);
+                emu_set_overscan(config_debug.debug ? 0 : config_video.overscan);
 
                 if (config_debug.debug)
                     emu_debug_step();
diff --git a/platforms/libretro/libretro.cpp b/platforms/libretro/libretro.cpp
index 3af5e9e5..6953a8cc 100644
--- a/platforms/libretro/libretro.cpp
+++ b/platforms/libretro/libretro.cpp
@@ -70,7 +70,7 @@ static const struct retro_variable vars[] = {
     { "gearsystem_mapper", "Mapper (restart); Auto|ROM|SEGA|Codemasters|Korean|MSX|Janggun|SG-1000" },
     { "gearsystem_timing", "Refresh Rate (restart); Auto|NTSC (60 Hz)|PAL (50 Hz)" },
     { "gearsystem_aspect_ratio", "Aspect Ratio (restart); 1:1 PAR|4:3 PAR|16:9 PAR" },
-    { "gearsystem_overscan", "Overscan; Disabled|Top+Bottom|Full" },
+    { "gearsystem_overscan", "Overscan; Disabled|Top+Bottom|Full (284 width)|Full (320 width)" },
     { "gearsystem_bios_sms", "Master System BIOS (restart); Disabled|Enabled" },
     { "gearsystem_bios_gg", "Game Gear BIOS (restart); Disabled|Enabled" },
     { "gearsystem_ym2413", "YM2413 (restart); Auto|Disabled"},
@@ -436,8 +436,10 @@ static void check_variables(void)
             core->GetVideo()->SetOverscan(Video::OverscanDisabled);
         else if (strcmp(var.value, "Top+Bottom") == 0)
             core->GetVideo()->SetOverscan(Video::OverscanTopBottom);
-        else if (strcmp(var.value, "Full") == 0)
-            core->GetVideo()->SetOverscan(Video::OverscanFull);
+        else if (strcmp(var.value, "Full (284 width)") == 0)
+            core->GetVideo()->SetOverscan(Video::OverscanFull284);
+        else if (strcmp(var.value, "Full (320 width)") == 0)
+            core->GetVideo()->SetOverscan(Video::OverscanFull320);
         else
             core->GetVideo()->SetOverscan(Video::OverscanDisabled);
     }
diff --git a/src/GearsystemCore.cpp b/src/GearsystemCore.cpp
index d84c4168..441ed7e5 100644
--- a/src/GearsystemCore.cpp
+++ b/src/GearsystemCore.cpp
@@ -261,8 +261,10 @@ bool GearsystemCore::GetRuntimeInfo(GS_RuntimeInfo& runtime_info)
             runtime_info.screen_width = GS_RESOLUTION_SMS_WIDTH;
             runtime_info.screen_height = m_pVideo->IsExtendedMode224() ? GS_RESOLUTION_SMS_HEIGHT_EXTENDED : GS_RESOLUTION_SMS_HEIGHT;
 
-            if (m_pVideo->GetOverscan() == Video::OverscanFull)
-                runtime_info.screen_width = GS_RESOLUTION_SMS_WIDTH + (2 * GS_RESOLUTION_SMS_OVERSCAN_H);
+            if (m_pVideo->GetOverscan() == Video::OverscanFull284)
+                runtime_info.screen_width = GS_RESOLUTION_SMS_WIDTH + GS_RESOLUTION_SMS_OVERSCAN_H_284_L + GS_RESOLUTION_SMS_OVERSCAN_H_284_R;
+            if (m_pVideo->GetOverscan() == Video::OverscanFull320)
+                runtime_info.screen_width = GS_RESOLUTION_SMS_WIDTH + GS_RESOLUTION_SMS_OVERSCAN_H_320_L + GS_RESOLUTION_SMS_OVERSCAN_H_320_R;
             if (m_pVideo->GetOverscan() != Video::OverscanDisabled)
                 runtime_info.screen_height = GS_RESOLUTION_SMS_HEIGHT + (2 * (m_pCartridge->IsPAL() ? GS_RESOLUTION_SMS_OVERSCAN_V_PAL : GS_RESOLUTION_SMS_OVERSCAN_V));
         }
diff --git a/src/Video.cpp b/src/Video.cpp
index 18d1939e..d975e7a3 100644
--- a/src/Video.cpp
+++ b/src/Video.cpp
@@ -915,7 +915,7 @@ void Video::Render24bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
 {
     int x = 0;
     int y = 0;
-    int overscan_h = 0;
+    int overscan_h_l = 0;
     int overscan_v = 0;
     int overscan_content_v = 0;
     int overscan_content_h = 0;
@@ -943,11 +943,18 @@ void Video::Render24bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
         overscan_total_height = overscan_content_v + (overscan_v * 2);
     }
 
-    if (overscan && (m_Overscan == OverscanFull))
+    if (overscan && (m_Overscan == OverscanFull320))
     {
         overscan_content_h = GS_RESOLUTION_MAX_WIDTH;
-        overscan_h = GS_RESOLUTION_SMS_OVERSCAN_H;
-        overscan_total_width = overscan_content_h + (overscan_h * 2);
+        overscan_h_l = GS_RESOLUTION_SMS_OVERSCAN_H_320_L;
+        overscan_total_width = overscan_content_h + overscan_h_l + GS_RESOLUTION_SMS_OVERSCAN_H_320_R;
+    }
+
+    if (overscan && (m_Overscan == OverscanFull284))
+    {
+        overscan_content_h = GS_RESOLUTION_MAX_WIDTH;
+        overscan_h_l = GS_RESOLUTION_SMS_OVERSCAN_H_284_L;
+        overscan_total_width = overscan_content_h + overscan_h_l + GS_RESOLUTION_SMS_OVERSCAN_H_284_R;
     }
 
     for (int i = 0, j = 0; j < buffer_size; j += 3)
@@ -955,7 +962,7 @@ void Video::Render24bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
         u16 src_color = 0;
         if (overscan_enabled)
         {
-            bool is_h_overscan = (overscan_h > 0) && (x < overscan_h || x >= (overscan_h + overscan_content_h));
+            bool is_h_overscan = (overscan_h_l > 0) && (x < overscan_h_l || x >= (overscan_h_l + overscan_content_h));
             bool is_v_overscan = (overscan_v > 0) && (y < overscan_v || y >= (overscan_v + overscan_content_v));
 
             if (is_h_overscan || is_v_overscan)
@@ -994,7 +1001,7 @@ void Video::Render16bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
 {
     int x = 0;
     int y = 0;
-    int overscan_h = 0;
+    int overscan_h_l = 0;
     int overscan_v = 0;
     int overscan_content_v = 0;
     int overscan_content_h = 0;
@@ -1040,11 +1047,18 @@ void Video::Render16bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
         overscan_total_height = overscan_content_v + (overscan_v * 2);
     }
 
-    if (overscan && (m_Overscan == OverscanFull))
+    if (overscan && (m_Overscan == OverscanFull320))
+    {
+        overscan_content_h = GS_RESOLUTION_MAX_WIDTH;
+        overscan_h_l = GS_RESOLUTION_SMS_OVERSCAN_H_320_L;
+        overscan_total_width = overscan_content_h + overscan_h_l + GS_RESOLUTION_SMS_OVERSCAN_H_320_R;
+    }
+
+    if (overscan && (m_Overscan == OverscanFull284))
     {
         overscan_content_h = GS_RESOLUTION_MAX_WIDTH;
-        overscan_h = GS_RESOLUTION_SMS_OVERSCAN_H;
-        overscan_total_width = overscan_content_h + (overscan_h * 2);
+        overscan_h_l = GS_RESOLUTION_SMS_OVERSCAN_H_284_L;
+        overscan_total_width = overscan_content_h + overscan_h_l + GS_RESOLUTION_SMS_OVERSCAN_H_284_R;
     }
 
     for (int i = 0, j = 0; j < buffer_size; j += 2)
@@ -1052,7 +1066,7 @@ void Video::Render16bit(u16* srcFrameBuffer, u8* dstFrameBuffer, GS_Color_Format
         u16 src_color = 0;
         if (overscan_enabled)
         {
-            bool is_h_overscan = (overscan_h > 0) && (x < overscan_h || x >= (overscan_h + overscan_content_h));
+            bool is_h_overscan = (overscan_h_l > 0) && (x < overscan_h_l || x >= (overscan_h_l + overscan_content_h));
             bool is_v_overscan = (overscan_v > 0) && (y < overscan_v || y >= (overscan_v + overscan_content_v));
 
             if (is_h_overscan || is_v_overscan)
diff --git a/src/Video.h b/src/Video.h
index 52134435..9433b098 100644
--- a/src/Video.h
+++ b/src/Video.h
@@ -38,7 +38,8 @@ class Video
     {
         OverscanDisabled,
         OverscanTopBottom,
-        OverscanFull
+        OverscanFull284,
+        OverscanFull320
     };
 
 public:
diff --git a/src/definitions.h b/src/definitions.h
index 11db3894..15ed3658 100644
--- a/src/definitions.h
+++ b/src/definitions.h
@@ -98,7 +98,10 @@ typedef void (*RamChangedCallback) (void);
 #define GS_RESOLUTION_SMS_WIDTH 256
 #define GS_RESOLUTION_SMS_HEIGHT 192
 #define GS_RESOLUTION_SMS_HEIGHT_EXTENDED 224
-#define GS_RESOLUTION_SMS_OVERSCAN_H 32
+#define GS_RESOLUTION_SMS_OVERSCAN_H_320_L 32
+#define GS_RESOLUTION_SMS_OVERSCAN_H_320_R 32
+#define GS_RESOLUTION_SMS_OVERSCAN_H_284_L 13
+#define GS_RESOLUTION_SMS_OVERSCAN_H_284_R 15
 #define GS_RESOLUTION_SMS_OVERSCAN_V 24
 #define GS_RESOLUTION_SMS_OVERSCAN_V_PAL 48