diff --git a/layout/tables/nsTableFrame.cpp b/layout/tables/nsTableFrame.cpp
index c914f11af705..b18cd316ac1e 100644
--- a/layout/tables/nsTableFrame.cpp
+++ b/layout/tables/nsTableFrame.cpp
@@ -182,9 +182,10 @@ nsTableFrame::Init(nsIContent*       aContent,
       mTableLayoutStrategy = new FixedTableLayoutStrategy(this);
     }
   } else {
-    // set my width, because all frames in a table flow are the same width and
-    // code in nsTableOuterFrame depends on this being set
-    mRect.width = aPrevInFlow->GetSize().width;
+    // Set my isize, because all frames in a table flow are the same isize and
+    // code in nsTableOuterFrame depends on this being set.
+    WritingMode wm = GetWritingMode();
+    SetSize(LogicalSize(wm, aPrevInFlow->ISize(wm), BSize(wm)));
   }
 }