Index: binaries/data/mods/public/gui/session/unit_actions.js
===================================================================
--- binaries/data/mods/public/gui/session/unit_actions.js
+++ binaries/data/mods/public/gui/session/unit_actions.js
@@ -631,7 +631,7 @@
 		"getActionInfo": function(entState, targetState)
 		{
 			if (!entState.canGarrison || !targetState.garrisonHolder ||
-			    !playerCheck(entState, targetState, ["Player", "MutualAlly"]))
+			    !playerCheck(entState, targetState, targetState.garrisonHolder.allowedPlayers))
 				return false;
 
 			let tooltip = sprintf(translate("Current garrison: %(garrisoned)s/%(capacity)s"), {
Index: binaries/data/mods/public/simulation/components/GarrisonHolder.js
===================================================================
--- binaries/data/mods/public/simulation/components/GarrisonHolder.js
+++ binaries/data/mods/public/simulation/components/GarrisonHolder.js
@@ -31,6 +31,20 @@
 		"</element>" +
 	"</optional>" +
 	"<optional>" +
+		"<element name='AllowedPlayers' a:help='What diplomatic attitude the owner of an entity has to have to be able to garrison.'>" +
+			"<list>" +
+				"<oneOrMore>" +
+					"<choice>" +
+						"<value>Player</value>" +
+						"<value>MutualAlly</value>" +
+						"<value>Neutral</value>" +
+						"<value>Enemy</value>" +
+					"</choice>" +
+				"</oneOrMore>" +
+			"</list>" +
+		"</element>" +
+	"</optional>" +
+	"<optional>" +
 		"<element name='VisibleGarrisonPoints' a:help='Points that will be used to visibly garrison a unit'>" +
 			"<zeroOrMore>" +
 				"<element a:help='Element containing the offset coordinates'>" +
@@ -65,6 +79,7 @@
 {
 	// Garrisoned Units
 	this.entities = [];
+	this.allowedPlayers = this.template.AllowedPlayers ? this.template.AllowedPlayers.split(/\s+/) : ["Player", "MutualAlly"];
 	this.timer = undefined;
 	this.allowGarrisoning = new Map();
 	this.visibleGarrisonPoints = [];
@@ -106,6 +121,15 @@
 };
 
 /**
+ * What diplomatic stances are allowd to join.
+ * @return {string[]} An array containing the allowed diplomacies to garrison.
+ */
+GarrisonHolder.prototype.GetAllowedPlayers = function()
+{
+	return ApplyValueModificationsToEntity("GarrisonHolder/AllowedPlayers", this.allowedPlayers, this.entity);
+};
+
+/**
  * @return {Array} unit classes which can be garrisoned inside this
  * particular entity. Obtained from the entity's template.
  */
@@ -167,7 +191,7 @@
 	if (!this.IsGarrisoningAllowed())
 		return false;
 
-	if (!IsOwnedByMutualAllyOfEntity(ent, this.entity))
+	if (!this.IsAllowedByDiplomacy(ent))
 		return false;
 
 	let cmpIdentity = Engine.QueryInterface(ent, IID_Identity);
@@ -509,6 +533,28 @@
 };
 
 /**
+ * Used to check if the garrisoning entity's diplomatic status is right for garrisoning this entity.
+ * @param {number} ent - The entity ID to check for.
+ *
+ * @return {boolean} - Whether garrisoning is allowed purely on diplomatic grounds.
+ */
+GarrisonHolder.prototype.IsAllowedByDiplomacy = function(ent)
+{
+	if (!this.template.AllowedPlayers)
+		return IsOwnedByMutualAllyOfEntity(this.entity, ent);
+
+	let owner = INVALID_PLAYER;
+	let cmpOwner = Engine.QueryInterface(this.entity, IID_Ownership);
+	if (cmpOwner)
+		owner = cmpOwner.GetOwner();
+	let allowedPlayers = this.GetAllowedPlayers();
+	return allowedPlayers.indexOf("Player") != -1 && IsOwnedByPlayer(owner, ent) ||
+		allowedPlayers.indexOf("MutualAlly") != -1 && IsOwnedByMutualAllyOfEntity(this.entity, ent) ||
+		allowedPlayers.indexOf("Neutral") != -1 && IsOwnedByNeutralOfEntity(this.entity, ent) ||
+		allowedPlayers.indexOf("Enemy") != -1 && IsOwnedByEnemyOfEntity(this.entity, ent);
+};
+
+/**
  * Called every second. Heals garrisoned units.
  */
 GarrisonHolder.prototype.HealTimeout = function(data)
@@ -564,7 +610,7 @@
 	// The ownership change may be on the garrisonholder
 	if (this.entity == msg.entity)
 	{
-		let entities = this.entities.filter(ent => msg.to == INVALID_PLAYER || !IsOwnedByMutualAllyOfEntity(this.entity, ent));
+		let entities = this.entities.filter(ent => msg.to == INVALID_PLAYER || !this.IsAllowedByDiplomacy(ent));
 
 		if (entities.length)
 			this.EjectOrKill(entities);
@@ -588,7 +634,7 @@
 				if (point.entity == msg.entity)
 					point.entity = null;
 		}
-		else if (msg.to == INVALID_PLAYER || !IsOwnedByMutualAllyOfEntity(this.entity, msg.entity))
+		else if (msg.to == INVALID_PLAYER || !this.IsAllowedByDiplomacy(msg.entity))
 			this.EjectOrKill([msg.entity]);
 	}
 };
Index: binaries/data/mods/public/simulation/components/GuiInterface.js
===================================================================
--- binaries/data/mods/public/simulation/components/GuiInterface.js
+++ binaries/data/mods/public/simulation/components/GuiInterface.js
@@ -360,7 +360,8 @@
 			"buffHeal": cmpGarrisonHolder.GetHealRate(),
 			"allowedClasses": cmpGarrisonHolder.GetAllowedClasses(),
 			"capacity": cmpGarrisonHolder.GetCapacity(),
-			"garrisonedEntitiesCount": cmpGarrisonHolder.GetGarrisonedEntitiesCount()
+			"garrisonedEntitiesCount": cmpGarrisonHolder.GetGarrisonedEntitiesCount(),
+			"allowedPlayers": cmpGarrisonHolder.GetAllowedPlayers()
 		};
 
 	ret.canGarrison = !!Engine.QueryInterface(ent, IID_Garrisonable);
Index: binaries/data/mods/public/simulation/components/UnitAI.js
===================================================================
--- binaries/data/mods/public/simulation/components/UnitAI.js
+++ binaries/data/mods/public/simulation/components/UnitAI.js
@@ -5767,7 +5767,7 @@
 
 	// Verify that the target is owned by this entity's player or a mutual ally of this player
 	var cmpOwnership = Engine.QueryInterface(this.entity, IID_Ownership);
-	if (!cmpOwnership || !(IsOwnedByPlayer(cmpOwnership.GetOwner(), target) || IsOwnedByMutualAllyOfPlayer(cmpOwnership.GetOwner(), target)))
+	if (!cmpOwnership || !cmpGarrisonHolder.IsAllowedByDiplomacy(this.entity))
 		return false;
 
 	// Don't let animals garrison for now
Index: binaries/data/mods/public/simulation/components/tests/test_GarrisonHolder.js
===================================================================
--- binaries/data/mods/public/simulation/components/tests/test_GarrisonHolder.js
+++ binaries/data/mods/public/simulation/components/tests/test_GarrisonHolder.js
@@ -33,14 +33,15 @@
 });
 
 AddMock(player, IID_Player, {
-	"IsAlly": id => true,
-	"IsMutualAlly": id => true,
+	"IsAlly": id => id != enemyPlayer,
+	"IsMutualAlly": id => id != enemyPlayer,
+	"IsEnemy": id => id == enemyPlayer,
 	"GetPlayerID": () => player
 });
 
 AddMock(friendlyPlayer, IID_Player, {
-	"IsAlly": id => true,
-	"IsMutualAlly": id => true,
+	"IsAlly": id => id != enemyPlayer,
+	"IsMutualAlly": id => id != enemyPlayer,
 	"GetPlayerID": () => friendlyPlayer
 });
 
@@ -168,3 +169,29 @@
 TS_ASSERT_EQUALS(cmpGarrisonHolder.IsFull(), false);
 TS_ASSERT_EQUALS(cmpGarrisonHolder.UnloadAll(), true);
 TS_ASSERT_UNEVAL_EQUALS(cmpGarrisonHolder.GetEntities(), []);
+
+// Test allowed players.
+cmpGarrisonHolder = ConstructComponent(garrisonHolderId, "GarrisonHolder", {
+	"Max": 10,
+	"List": { "_string": "Infantry+Cavalry" },
+	"EjectHealth": 0.1,
+	"EjectClassesOnDestroy": { "_string": "Infantry" },
+	"BuffHeal": 1,
+	"LoadingRange": 2.1,
+	"Pickup": false,
+	"AllowedPlayers": "Enemy",
+	"VisibleGarrisonPoints": {
+		"archer1": {
+			"X": 12,
+			"Y": 5,
+			"Z": 6
+		},
+		"archer2": {
+			"X": 15,
+			"Y": 5,
+			"Z": 6
+		}
+	}
+});
+TS_ASSERT_EQUALS(cmpGarrisonHolder.IsAllowedToGarrison(enemyUnitId), true);
+TS_ASSERT_EQUALS(cmpGarrisonHolder.IsAllowedToGarrison(unitToGarrisonId), false);
Index: binaries/data/mods/public/simulation/helpers/Commands.js
===================================================================
--- binaries/data/mods/public/simulation/helpers/Commands.js
+++ binaries/data/mods/public/simulation/helpers/Commands.js
@@ -468,14 +468,6 @@
 
 	"garrison": function(player, cmd, data)
 	{
-		// Verify that the building can be controlled by the player or is mutualAlly
-		if (!CanControlUnitOrIsAlly(cmd.target, player, data.controlAllUnits))
-		{
-			if (g_DebugCommands)
-				warn("Invalid command: garrison target cannot be controlled by player "+player+" (or ally): "+uneval(cmd));
-			return;
-		}
-
 		GetFormationUnitAIs(data.entities, player).forEach(cmpUnitAI => {
 			cmpUnitAI.Garrison(cmd.target, cmd.queued);
 		});
Index: binaries/data/mods/public/simulation/helpers/Player.js
===================================================================
--- binaries/data/mods/public/simulation/helpers/Player.js
+++ binaries/data/mods/public/simulation/helpers/Player.js
@@ -277,6 +277,16 @@
 	return IsOwnedByEntityHelper(entity, target, "IsMutualAlly");
 }
 
+function IsOwnedByNeutralOfEntity(entity, target)
+{
+	return IsOwnedByEntityHelper(entity, target, "IsNeutral");
+}
+
+function IsOwnedByEnemyOfEntity(entity, target)
+{
+	return IsOwnedByEntityHelper(entity, target, "IsEnemy");
+}
+
 function IsOwnedByEntityHelper(entity, target, check)
 {
 	// Figure out which player controls us
@@ -353,6 +363,8 @@
 Engine.RegisterGlobal("QueryBuilderListInterface", QueryBuilderListInterface);
 Engine.RegisterGlobal("IsOwnedByAllyOfEntity", IsOwnedByAllyOfEntity);
 Engine.RegisterGlobal("IsOwnedByMutualAllyOfEntity", IsOwnedByMutualAllyOfEntity);
+Engine.RegisterGlobal("IsOwnedByNeutralOfEntity", IsOwnedByNeutralOfEntity);
+Engine.RegisterGlobal("IsOwnedByEnemyOfEntity", IsOwnedByEnemyOfEntity);
 Engine.RegisterGlobal("IsOwnedByPlayer", IsOwnedByPlayer);
 Engine.RegisterGlobal("IsOwnedByGaia", IsOwnedByGaia);
 Engine.RegisterGlobal("IsOwnedByAllyOfPlayer", IsOwnedByAllyOfPlayer);