diff --git a/layout/forms/nsMeterFrame.cpp b/layout/forms/nsMeterFrame.cpp
index 629ae987e5df..553863fd9868 100644
--- a/layout/forms/nsMeterFrame.cpp
+++ b/layout/forms/nsMeterFrame.cpp
@@ -135,7 +135,7 @@ nsMeterFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
                              const nsHTMLReflowState& aReflowState,
                              nsReflowStatus&          aStatus)
 {
-  bool vertical = StyleDisplay()->mOrient == NS_STYLE_ORIENT_VERTICAL;
+  bool vertical = ResolvedOrientationIsVertical();
   WritingMode wm = aBarFrame->GetWritingMode();
   LogicalSize availSize = aReflowState.ComputedSize(wm);
   availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
@@ -158,7 +158,7 @@ nsMeterFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
 
   size = NSToCoordRound(size * position);
 
-  if (!vertical && StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
+  if (!vertical && (wm.IsVertical() ? wm.IsVerticalRL() : !wm.IsBidiLTR())) {
     xoffset += aReflowState.ComputedWidth() - size;
   }
 
@@ -230,7 +230,7 @@ nsMeterFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
   LogicalSize autoSize(wm);
   autoSize.BSize(wm) = autoSize.ISize(wm) = fontMet->Font().size; // 1em
 
-  if (StyleDisplay()->mOrient == NS_STYLE_ORIENT_VERTICAL) {
+  if (ResolvedOrientationIsVertical()) {
     autoSize.Height(wm) *= 5; // 5em
   } else {
     autoSize.Width(wm) *= 5; // 5em
@@ -246,14 +246,14 @@ nsMeterFrame::GetMinISize(nsRenderingContext *aRenderingContext)
   NS_ENSURE_SUCCESS(
       nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet)), 0);
 
-  nscoord minWidth = fontMet->Font().size; // 1em
+  nscoord minISize = fontMet->Font().size; // 1em
 
-  if (StyleDisplay()->mOrient == NS_STYLE_ORIENT_HORIZONTAL) {
-    // The orientation is horizontal
-    minWidth *= 5; // 5em
+  if (ResolvedOrientationIsVertical() == GetWritingMode().IsVertical()) {
+    // The orientation is inline
+    minISize *= 5; // 5em
   }
 
-  return minWidth;
+  return minISize;
 }
 
 nscoord
diff --git a/layout/forms/nsProgressFrame.cpp b/layout/forms/nsProgressFrame.cpp
index 759a5ef6ff81..86b030707e62 100644
--- a/layout/forms/nsProgressFrame.cpp
+++ b/layout/forms/nsProgressFrame.cpp
@@ -139,7 +139,7 @@ nsProgressFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
                                 const nsHTMLReflowState& aReflowState,
                                 nsReflowStatus&          aStatus)
 {
-  bool vertical = StyleDisplay()->mOrient == NS_STYLE_ORIENT_VERTICAL;
+  bool vertical = ResolvedOrientationIsVertical();
   WritingMode wm = aBarFrame->GetWritingMode();
   LogicalSize availSize = aReflowState.ComputedSize(wm);
   availSize.BSize(wm) = NS_UNCONSTRAINEDSIZE;
@@ -158,7 +158,7 @@ nsProgressFrame::ReflowBarFrame(nsIFrame*                aBarFrame,
     size *= position;
   }
 
-  if (!vertical && StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
+  if (!vertical && (wm.IsVertical() ? wm.IsVerticalRL() : !wm.IsBidiLTR())) {
     xoffset += aReflowState.ComputedWidth() - size;
   }
 
@@ -236,7 +236,7 @@ nsProgressFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
     NSToCoordRound(StyleFont()->mFont.size *
                    nsLayoutUtils::FontSizeInflationFor(this)); // 1em
 
-  if (StyleDisplay()->mOrient == NS_STYLE_ORIENT_VERTICAL) {
+  if (ResolvedOrientationIsVertical()) {
     autoSize.Height(wm) *= 10; // 10em
   } else {
     autoSize.Width(wm) *= 10; // 10em
@@ -252,14 +252,14 @@ nsProgressFrame::GetMinISize(nsRenderingContext *aRenderingContext)
   NS_ENSURE_SUCCESS(
       nsLayoutUtils::GetFontMetricsForFrame(this, getter_AddRefs(fontMet)), 0);
 
-  nscoord minWidth = fontMet->Font().size; // 1em
+  nscoord minISize = fontMet->Font().size; // 1em
 
-  if (StyleDisplay()->mOrient == NS_STYLE_ORIENT_HORIZONTAL) {
-    // The orientation is horizontal
-    minWidth *= 10; // 10em
+  if (ResolvedOrientationIsVertical() == GetWritingMode().IsVertical()) {
+    // The orientation is inline
+    minISize *= 10; // 10em
   }
 
-  return minWidth;
+  return minISize;
 }
 
 nscoord
diff --git a/layout/generic/nsContainerFrame.cpp b/layout/generic/nsContainerFrame.cpp
index 912f05b94603..dd8d1d35c112 100644
--- a/layout/generic/nsContainerFrame.cpp
+++ b/layout/generic/nsContainerFrame.cpp
@@ -1679,6 +1679,24 @@ nsContainerFrame::PullNextInFlowChild(ContinuationTraversingState& aState)
   return frame;
 }
 
+bool
+nsContainerFrame::ResolvedOrientationIsVertical()
+{
+  uint8_t orient = StyleDisplay()->mOrient;
+  switch (orient) {
+    case NS_STYLE_ORIENT_HORIZONTAL:
+      return false;
+    case NS_STYLE_ORIENT_VERTICAL:
+      return true;
+    case NS_STYLE_ORIENT_INLINE:
+      return GetWritingMode().IsVertical();
+    case NS_STYLE_ORIENT_BLOCK:
+      return !GetWritingMode().IsVertical();
+  }
+  NS_NOTREACHED("unexpected -moz-orient value");
+  return false;
+}
+
 nsOverflowContinuationTracker::nsOverflowContinuationTracker(nsContainerFrame* aFrame,
                                                              bool              aWalkOOFFrames,
                                                              bool              aSkipOverflowContainerChildren)
diff --git a/layout/generic/nsContainerFrame.h b/layout/generic/nsContainerFrame.h
index a638c56ab09c..59bd5bb5335b 100644
--- a/layout/generic/nsContainerFrame.h
+++ b/layout/generic/nsContainerFrame.h
@@ -613,6 +613,12 @@ protected:
 
   // ==========================================================================
 
+  // Helper used by Progress and Meter frames. Returns true if the bar should
+  // be rendered vertically, based on writing-mode and -moz-orient properties.
+  bool ResolvedOrientationIsVertical();
+
+  // ==========================================================================
+
   nsFrameList mFrames;
 };