diff --git a/src/p_lnspec.cpp b/src/p_lnspec.cpp
index 49aac88c5..2462f036c 100644
--- a/src/p_lnspec.cpp
+++ b/src/p_lnspec.cpp
@@ -1053,10 +1053,25 @@ FUNC(LS_Teleport_NoFog)
 // Teleport_NoFog (tid, useang, sectortag, keepheight)
 {
 	int flags = 0;
-	if (!arg1)
+	switch (arg1)
 	{
+	case 0:
 		flags |= TELF_KEEPORIENTATION;
+		break;
+
+	default:
+	case 1:
+		break;
+
+	case 2:
+		flags |= TELF_KEEPORIENTATION | TELF_ROTATEBOOM;	// adjust to exit thing like Boom (i.e. with incorrect reversed angle)
+		break;
+
+	case 3:
+		flags |= TELF_KEEPORIENTATION | TELF_ROTATEBOOMINVERSE;	// adjust to exit thing correctly
+		break;
 	}
+
 	if (arg3)
 	{
 		flags |= TELF_KEEPHEIGHT;
diff --git a/src/p_spec.h b/src/p_spec.h
index 0899c6268..7bd04f48c 100644
--- a/src/p_spec.h
+++ b/src/p_spec.h
@@ -666,6 +666,8 @@ enum
 	TELF_KEEPORIENTATION	= 4,
 	TELF_KEEPVELOCITY		= 8,
 	TELF_KEEPHEIGHT			= 16,
+	TELF_ROTATEBOOM			= 32,
+	TELF_ROTATEBOOMINVERSE	= 64,
 };
 
 //Spawns teleport fog. Pass the actor to pluck TeleFogFromType and TeleFogToType. 'from' determines if this is the fog to spawn at the old position (true) or new (false).
diff --git a/src/p_teleport.cpp b/src/p_teleport.cpp
index 40ae4efed..a3dbd0899 100644
--- a/src/p_teleport.cpp
+++ b/src/p_teleport.cpp
@@ -349,13 +349,14 @@ bool EV_Teleport (int tid, int tag, line_t *line, int side, AActor *thing, int f
 		return false;
 	}
 	// [RH] Lee Killough's changes for silent teleporters from BOOM
-	if ((flags & TELF_KEEPORIENTATION) && line)
+	if ((flags & (TELF_ROTATEBOOM|TELF_ROTATEBOOMINVERSE)) && line)
 	{
 		// Get the angle between the exit thing and source linedef.
 		// Rotate 90 degrees, so that walking perpendicularly across
 		// teleporter linedef causes thing to exit in the direction
 		// indicated by the exit thing.
 		angle = line->Delta().Angle() - searcher->Angles.Yaw + 90.;
+		if (flags & TELF_ROTATEBOOMINVERSE) angle = -angle;
 
 		// Sine, cosine of angle adjustment
 		s = angle.Sin();
@@ -382,14 +383,17 @@ bool EV_Teleport (int tid, int tag, line_t *line, int side, AActor *thing, int f
 	if (P_Teleport (thing, DVector3(searcher->Pos(), z), searcher->Angles.Yaw + badangle, flags))
 	{
 		// [RH] Lee Killough's changes for silent teleporters from BOOM
-		if (!(flags & TELF_DESTFOG) && line && (flags & TELF_KEEPORIENTATION))
+		if (line)
 		{
-			// Rotate thing according to difference in angles
-			thing->Angles.Yaw += angle;
+			if (flags & (TELF_ROTATEBOOM| TELF_ROTATEBOOMINVERSE))
+			{
+				// Rotate thing according to difference in angles (or not - Boom got the direction wrong here.)
+				thing->Angles.Yaw += angle;
 
-			// Rotate thing's velocity to come out of exit just like it entered
-			thing->Vel.X = vx*c - vy*s;
-			thing->Vel.Y = vy*c + vx*s;
+				// Rotate thing's velocity to come out of exit just like it entered
+				thing->Vel.X = vx*c - vy*s;
+				thing->Vel.Y = vy*c + vx*s;
+			}
 		}
 		if (vx == 0 && vy == 0 && thing->player != NULL && thing->player->mo == thing && !predicting)
 		{
diff --git a/wadsrc/static/xlat/base.txt b/wadsrc/static/xlat/base.txt
index d125c4903..8a99ba318 100644
--- a/wadsrc/static/xlat/base.txt
+++ b/wadsrc/static/xlat/base.txt
@@ -209,10 +209,10 @@ include "xlat/defines.i"
 204 = USE,		Ceiling_LowerToHighestFloor (tag, C_SLOW)
 205 = USE|REP,		Ceiling_LowerToLowest (tag, C_SLOW)
 206 = USE|REP,		Ceiling_LowerToHighestFloor (tag, C_SLOW)
-207 = WALK|MONST,	Teleport_NoFog (0, 0, tag, 1)
-208 = WALK|REP|MONST,	Teleport_NoFog (0, 0, tag, 1)
-209 = USE|MONST,	Teleport_NoFog (0, 0, tag, 1)
-210 = USE|REP|MONST,	Teleport_NoFog (0, 0, tag, 1)
+207 = WALK|MONST,	Teleport_NoFog (0, 2, tag, 1)
+208 = WALK|REP|MONST,	Teleport_NoFog (0, 2, tag, 1)
+209 = USE|MONST,	Teleport_NoFog (0, 2, tag, 1)
+210 = USE|REP|MONST,	Teleport_NoFog (0, 2, tag, 1)
 211 = USE|REP,		Plat_ToggleCeiling (tag)
 212 = WALK|REP,		Plat_ToggleCeiling (tag)
 213 = 0,		Transfer_FloorLight (tag)
@@ -270,8 +270,8 @@ include "xlat/defines.i"
 265 = MONWALK|REP,	Teleport_Line (tag, tag, 1)
 266 = MONWALK,		Teleport_Line (tag, tag, 0)
 267 = MONWALK|REP,	Teleport_Line (tag, tag, 0)
-268 = MONWALK,		Teleport_NoFog (0, 0, tag, 1)
-269 = MONWALK|REP,	Teleport_NoFog (0, 0, tag, 1)
+268 = MONWALK,		Teleport_NoFog (0, 2, tag, 1)
+269 = MONWALK|REP,	Teleport_NoFog (0, 2, tag, 1)
 
 /****** MBF linetypes ******/