Index: binaries/data/mods/public/gui/session/session.js
===================================================================
--- binaries/data/mods/public/gui/session/session.js
+++ binaries/data/mods/public/gui/session/session.js
@@ -407,14 +407,13 @@
 }
 
 /**
- * Returns the entity itself except when garrisoned where it returns its garrisonHolder
+ * @return {number} - The entity itself except when garrisoned then its garrisonHolder.
  */
 function getEntityOrHolder(ent)
 {
 	let entState = GetEntityState(ent);
-	if (entState && !entState.position && entState.unitAI && entState.unitAI.orders.length &&
-			entState.unitAI.orders[0].type == "Garrison")
-		return getEntityOrHolder(entState.unitAI.orders[0].data.target);
+	if (entState && !entState.position && entState.garrisonable && entState.garrisonable.garrisonHolder != INVALID_ENTITY)
+		return getEntityOrHolder(entState.garrisonable.garrisonHolder);
 
 	return ent;
 }
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
@@ -720,7 +720,7 @@
 		},
 		"getActionInfo": function(entState, targetState)
 		{
-			if (!entState.canGarrison || !targetState.garrisonHolder ||
+			if (!entState.garrisonable || !targetState.garrisonHolder ||
 			    !playerCheck(entState, targetState, ["Player", "MutualAlly"]))
 				return false;
 
@@ -1264,7 +1264,9 @@
 		"getInfo": function(entStates)
 		{
 			if (entStates.every(entState => {
-				if (!entState.unitAI || !entState.turretParent)
+				if (!entState.unitAI ||
+					!entState.garrisonable ||
+					entState.garrisonable.garrisonHolder == INVALID_ENTITY)
 					return true;
 				let parent = GetEntityState(entState.turretParent);
 				return !parent || !parent.garrisonHolder || parent.garrisonHolder.entities.indexOf(entState.id) == -1;
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
@@ -150,11 +150,8 @@
 		return false;
 
 	let cmpIdentity = Engine.QueryInterface(entity, IID_Identity);
-	if (!cmpIdentity)
-		return false;
-
-	let entityClasses = cmpIdentity.GetClassesList();
-	return MatchesClassList(entityClasses, this.allowedClasses) && !!Engine.QueryInterface(entity, IID_Garrisonable);
+	return cmpIdentity &&
+		MatchesClassList(cmpIdentity.GetClassesList(), this.allowedClasses);
 };
 
 /**
@@ -171,6 +168,10 @@
 	if (!this.HasEnoughHealth())
 		return false;
 
+	let cmpGarrisonable = Engine.QueryInterface(entity, IID_Garrisonable);
+	if (!cmpGarrisonable || !cmpGarrisonable.Garrison(this.entity))
+		return false;
+
 	if (!this.timer && this.GetHealRate() > 0)
 	{
 		let cmpTimer = Engine.QueryInterface(SYSTEM_ENTITY, IID_Timer);
@@ -264,6 +265,10 @@
 			cmpEntPosition.SetYRotation(cmpPosition.GetPosition().horizAngleTo(pos));
 	}
 
+	let cmpGarrisonable = Engine.QueryInterface(entity, IID_Garrisonable);
+	if (cmpGarrisonable)
+		cmpGarrisonable.UnGarrison();
+
 	Engine.PostMessage(this.entity, MT_GarrisonedUnitsChanged, {
 		"added": [],
 		"removed": [entity],
Index: binaries/data/mods/public/simulation/components/Garrisonable.js
===================================================================
--- binaries/data/mods/public/simulation/components/Garrisonable.js
+++ binaries/data/mods/public/simulation/components/Garrisonable.js
@@ -4,8 +4,36 @@
 
 Garrisonable.prototype.Init = function()
 {
+	this.garrisonHolder = INVALID_ENTITY;
 };
 
-Garrisonable.prototype.Serialize = null;
+/**
+ * @return {number} - The entity ID of the entity this entity is garrisoned in.
+ */
+Garrisonable.prototype.GetHolderID = function()
+{
+	return this.garrisonHolder;
+};
+
+/**
+ * @param {number} entity - The entity ID of the entity this entity is being garrisoned in.
+ * @return {boolean} - Whether garrisoning succeeded.
+ */
+Garrisonable.prototype.Garrison = function(entity)
+{
+	if (this.garrisonHolder != INVALID_ENTITY)
+		return false;
+
+	this.garrisonHolder = entity;
+	return true;
+};
+
+/**
+ * Resets the garrisonHolder.
+ */
+Garrisonable.prototype.UnGarrison = function()
+{
+	this.garrisonHolder = INVALID_ENTITY;
+};
 
 Engine.RegisterComponentType(IID_Garrisonable, "Garrisonable", Garrisonable);
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
@@ -370,7 +370,11 @@
 			"turretPoints": cmpTurretHolder.GetTurretPoints()
 		};
 
-	ret.canGarrison = !!Engine.QueryInterface(ent, IID_Garrisonable);
+	let cmpGarrisonable = Engine.QueryInterface(ent, IID_Garrisonable);
+	if (cmpGarrisonable)
+		ret.garrisonable = {
+			"garrisonHolder": cmpGarrisonable.GetHolderID()
+		};
 
 	let cmpUnitAI = Engine.QueryInterface(ent, IID_UnitAI);
 	if (cmpUnitAI)
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
@@ -3478,13 +3478,11 @@
 
 UnitAI.prototype.GetGarrisonHolder = function()
 {
-	if (this.IsGarrisoned())
-	{
-		for (let order of this.orderQueue)
-			if (order.type == "Garrison")
-				return order.data.target;
-	}
-	return INVALID_ENTITY;
+	if (!this.isGarrisoned)
+		return INVALID_ENTITY;
+
+	let cmpGarrisonable = Engine.QueryInterface(this.entity, IID_Garrisonable);
+	return cmpGarrisonable ? cmpGarrisonable.GetHolderID() : INVALID_ENTITY;
 };
 
 UnitAI.prototype.ShouldRespondToEndOfAlert = function()
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
@@ -68,7 +68,10 @@
 			"GetOwner": () => friendlyPlayer
 		});
 
-	AddMock(i, IID_Garrisonable, {});
+	AddMock(i, IID_Garrisonable, {
+		"Garrison": entity => true,
+		"UnGarrison": () => {}
+	});
 
 	AddMock(i, IID_Position, {
 		"GetHeightOffset": () => 0,
@@ -212,7 +215,10 @@
 AddMock(siegeEngineId, IID_Ownership, {
 	"GetOwner": () => currentSiegePlayer
 });
-AddMock(siegeEngineId, IID_Garrisonable, {});
+AddMock(siegeEngineId, IID_Garrisonable, {
+	"Garrison": entity => true,
+	"UnGarrison": () => {}
+});
 let cavalryId = 46;
 AddMock(cavalryId, IID_Identity, {
 	"GetClassesList": () => ["Infantry", "Ranged"]
@@ -230,7 +236,10 @@
 AddMock(cavalryId, IID_Ownership, {
 	"GetOwner": () => currentCavalryPlayer
 });
-AddMock(cavalryId, IID_Garrisonable, {});
+AddMock(cavalryId, IID_Garrisonable, {
+	"Garrison": entity => true,
+	"UnGarrison": () => {}
+});
 TS_ASSERT(cmpGarrisonHolder.Garrison(siegeEngineId));
 TS_ASSERT_EQUALS(cmpGarrisonHolder.GetGarrisonedEntitiesCount(), 1);
 cmpGarrisonHolder.OnGlobalEntityRenamed({
Index: binaries/data/mods/public/simulation/components/tests/test_Garrisonable.js
===================================================================
--- /dev/null
+++ binaries/data/mods/public/simulation/components/tests/test_Garrisonable.js
@@ -0,0 +1,17 @@
+Engine.LoadComponentScript("interfaces/Garrisonable.js");
+Engine.LoadComponentScript("Garrisonable.js");
+
+const garrisonHolderID = 1;
+const garrisonableID = 2;
+
+let cmpGarrisonable = ConstructComponent(garrisonableID, "Garrisonable", {
+});
+
+TS_ASSERT(cmpGarrisonable.Garrison(garrisonHolderID));
+TS_ASSERT_UNEVAL_EQUALS(cmpGarrisonable.GetHolderID(), garrisonHolderID);
+
+TS_ASSERT(!cmpGarrisonable.Garrison(garrisonHolderID));
+TS_ASSERT_UNEVAL_EQUALS(cmpGarrisonable.GetHolderID(), garrisonHolderID);
+
+cmpGarrisonable.UnGarrison();
+TS_ASSERT_UNEVAL_EQUALS(cmpGarrisonable.GetHolderID(), INVALID_ENTITY);
Index: binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
===================================================================
--- binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
+++ binaries/data/mods/public/simulation/components/tests/test_GuiInterface.js
@@ -596,7 +596,6 @@
 	"needsRepair": false,
 	"needsHeal": true,
 	"builder": true,
-	"canGarrison": false,
 	"visibility": "visible",
 	"isBarterMarket": true,
 	"resourceTrickle": {