diff -r c85adae9a336 src/settings.cpp
--- a/src/settings.cpp	Sat Jul 30 01:01:06 2011 +0200
+++ b/src/settings.cpp	Sat Jul 30 11:15:57 2011 +0200
@@ -887,6 +887,13 @@
 	return true;
 }
 
+static bool ShowOnlyOwnSignsChanged(int32 p1)
+{
+	InvalidateWindowClassesData(WC_SIGN_LIST, -1);
+	MarkWholeScreenDirty();
+	return true;
+}
+
 static bool InvalidateVehTimetableWindow(int32 p1)
 {
 	InvalidateWindowClassesData(WC_VEHICLE_TIMETABLE, -2);
diff -r c85adae9a336 src/settings_type.h
--- a/src/settings_type.h	Sat Jul 30 01:01:06 2011 +0200
+++ b/src/settings_type.h	Sat Jul 30 11:15:57 2011 +0200
@@ -110,6 +110,7 @@
 	bool   station_show_coverage;            ///< whether to highlight coverage area
 	bool   persistent_buildingtools;         ///< keep the building tools active after usage
 	bool   expenses_layout;                  ///< layout of expenses window
+	bool   show_only_own_signs;              ///< hide signs (including signs of stations) that are not owned by local company
 
 	uint16 console_backlog_timeout;          ///< the minimum amount of time items should be in the console backlog before they will be removed in ~3 seconds granularity.
 	uint16 console_backlog_length;           ///< the minimum amount of items in the console backlog before items will be removed.
diff -r c85adae9a336 src/signs_gui.cpp
--- a/src/signs_gui.cpp	Sat Jul 30 01:01:06 2011 +0200
+++ b/src/signs_gui.cpp	Sat Jul 30 11:15:57 2011 +0200
@@ -26,6 +26,7 @@
 #include "string_func.h"
 #include "core/geometry_func.hpp"
 #include "hotkeys.h"
+#include "settings_type.h"
 
 #include "table/strings.h"
 #include "table/sprites.h"
@@ -116,11 +117,20 @@
 		return (filter_info.case_sensitive ? strstr(buf1, filter_info.string) : strcasestr(buf1, filter_info.string)) != NULL;
 	}
 
+	/** Filter sign list by owner */
+	static bool CDECL OwnerVisibilityFilter(const Sign * const *a, FilterInfo filter_info)
+	{
+		/* Hide sign if non-own signs are hidden in the viewport */
+		return !_settings_client.gui.show_only_own_signs || (*a)->owner == _local_company;
+	}
+
 	/** Filter out signs from the sign list that does not match the name filter */
 	void FilterSignList()
 	{
 		FilterInfo filter_info = {this->filter_string, this->match_case};
 		this->signs.Filter(&SignNameFilter, filter_info);
+		if (_settings_client.gui.show_only_own_signs)
+			this->signs.Filter(&OwnerVisibilityFilter, filter_info);
 	}
 };
 
@@ -199,7 +209,7 @@
 			/* There is no new string -> clear this->filter_string */
 			this->filter_string[0] = '\0';
 
-			this->signs.SetFilterState(false);
+			this->signs.SetFilterState(_settings_client.gui.show_only_own_signs); // keep sign list filtering active if only own signs should be shown
 			this->DisableWidget(SLW_FILTER_CLEAR_BTN);
 		}
 
@@ -374,10 +384,15 @@
 	 */
 	virtual void OnInvalidateData(int data = 0, bool gui_scope = true)
 	{
+		if (data == -1) {
+			/* The _settings_client.gui.show_only_own_signs setting has changed */
+			this->signs.SetFilterState(!StrEmpty(this->filter_string) || _settings_client.gui.show_only_own_signs);
+		}
+
 		/* When there is a filter string, we always need to rebuild the list even if
 		 * the amount of signs in total is unchanged, as the subset of signs that is
 		 * accepted by the filter might has changed. */
-		if (data == 0 || !StrEmpty(this->filter_string)) { // New or deleted sign, or there is a filter string
+		if (data == 0 || data == -1 || !StrEmpty(this->filter_string)) { // New or deleted sign, changed visibility setting or there is a filter string
 			/* This needs to be done in command-scope to enforce rebuilding before resorting invalid data */
 			this->signs.ForceRebuild();
 		} else { // Change of sign contents while there is no filter string
diff -r c85adae9a336 src/table/settings.ini
--- a/src/table/settings.ini	Sat Jul 30 01:01:06 2011 +0200
+++ b/src/table/settings.ini	Sat Jul 30 11:15:57 2011 +0200
@@ -33,6 +33,7 @@
 static bool CheckFreeformEdges(int32 p1);
 static bool ChangeDynamicEngines(int32 p1);
 static bool StationCatchmentChanged(int32 p1);
+static bool ShowOnlyOwnSignsChanged(int32 p1);
 static bool InvalidateVehTimetableWindow(int32 p1);
 static bool InvalidateCompanyLiveryWindow(int32 p1);
 static bool InvalidateNewGRFChangeWindows(int32 p1);
@@ -2353,6 +2354,12 @@
 str      = STR_CONFIG_SETTING_EXPENSES_LAYOUT
 proc     = RedrawScreen
 
+[SDTC_BOOL]
+var      = gui.show_only_own_signs
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+def      = false
+proc     = ShowOnlyOwnSignsChanged
+
 
 ; For the dedicated build we'll enable dates in logs by default.
 [SDTC_BOOL]
diff -r c85adae9a336 src/viewport.cpp
--- a/src/viewport.cpp	Sat Jul 30 01:01:06 2011 +0200
+++ b/src/viewport.cpp	Sat Jul 30 11:15:57 2011 +0200
@@ -1186,6 +1186,9 @@
 		/* Don't draw if the display options are disabled */
 		if (!HasBit(_display_opt, is_station ? DO_SHOW_STATION_NAMES : DO_SHOW_WAYPOINT_NAMES)) continue;
 
+		/* Don't draw if station is owned by another company and only own signs should be shown. Stations owned by town/none are never ignored. */
+		if (_settings_client.gui.show_only_own_signs && _local_company != st->owner && st->owner < MAX_COMPANIES) continue;
+
 		ViewportAddString(dpi, ZOOM_LVL_OUT_4X, &st->sign,
 				is_station ? STR_VIEWPORT_STATION : STR_VIEWPORT_WAYPOINT,
 				(is_station ? STR_VIEWPORT_STATION : STR_VIEWPORT_WAYPOINT) + 1, STR_NULL,
@@ -1201,6 +1204,9 @@
 
 	const Sign *si;
 	FOR_ALL_SIGNS(si) {
+		/* Don't draw if sign is owned by another company and only own signs should be shown. */
+		if (_settings_client.gui.show_only_own_signs && _local_company != si->owner) continue;
+
 		ViewportAddString(dpi, ZOOM_LVL_OUT_4X, &si->sign,
 				STR_WHITE_SIGN,
 				IsTransparencySet(TO_SIGNS) ? STR_VIEWPORT_SIGN_SMALL_WHITE : STR_VIEWPORT_SIGN_SMALL_BLACK, STR_NULL,