diff --git a/src/thingdef/thingdef_codeptr.cpp b/src/thingdef/thingdef_codeptr.cpp
index e9d85686b..51a920c8e 100644
--- a/src/thingdef/thingdef_codeptr.cpp
+++ b/src/thingdef/thingdef_codeptr.cpp
@@ -4265,6 +4265,7 @@ enum T_Flags
 	TF_USEACTORFOG =	0x00000100, // Use the actor's TeleFogSourceType and TeleFogDestType fogs.
 	TF_NOJUMP =			0x00000200, // Don't jump after teleporting.
 	TF_OVERRIDE =		0x00000400, // Ignore NOTELEPORT.
+	TF_SENSITIVEZ =		0x00000800, // Fail if the actor wouldn't fit in the position (for Z).
 };
 
 DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Teleport)
@@ -4329,6 +4330,20 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Teleport)
 		return;
 	}
 
+	
+	// [MC] By default, the function adjusts the actor's Z if it's below the floor or above the ceiling.
+	// This can be an issue as actors designed to maintain specific z positions wind up teleporting
+	// anyway when they should not, such as a floor rising above or ceiling lowering below the position
+	// of the spot.
+	if (flags & TF_SENSITIVEZ)
+	{
+		fixed_t posz = (flags & TF_USESPOTZ) ? spot->Z() : spot->floorz;
+		if ((posz + ref->height > spot->ceilingz) || (posz < spot->floorz))
+		{
+			ACTION_SET_RESULT(false);
+			return;
+		}
+	}
 	fixedvec3 prev = ref->Pos();
 	fixed_t aboveFloor = spot->Z() - spot->floorz;
 	fixed_t finalz = spot->floorz + aboveFloor;
@@ -4339,7 +4354,7 @@ DEFINE_ACTION_FUNCTION_PARAMS(AActor, A_Teleport)
 		finalz = spot->floorz;
 
 	//Take precedence and cooperate with telefragging first.
-	bool tele_result = P_TeleportMove(ref, spot->X(), spot->Y(), finalz, flags & TF_TELEFRAG);
+	bool tele_result = P_TeleportMove(ref, spot->X(), spot->Y(), finalz, !!(flags & TF_TELEFRAG));
 
 	if (!tele_result && (flags & TF_FORCED))
 	{
diff --git a/wadsrc/static/actors/constants.txt b/wadsrc/static/actors/constants.txt
index 213e2109d..a88290451 100644
--- a/wadsrc/static/actors/constants.txt
+++ b/wadsrc/static/actors/constants.txt
@@ -208,6 +208,7 @@ enum
 	TF_USEACTORFOG =	0x00000100, // Use the actor's TeleFogSourceType and TeleFogDestType fogs.
 	TF_NOJUMP =			0x00000200, // Don't jump after teleporting.
 	TF_OVERRIDE =		0x00000400, // Ignore NOTELEPORT.
+	TF_SENSITIVEZ =		0x00000800, // Fail if the actor wouldn't fit in the position (for Z).
 
 	TF_KEEPORIENTATION = TF_KEEPVELOCITY|TF_KEEPANGLE,
 	TF_NOFOG = TF_NOSRCFOG|TF_NODESTFOG,