diff --git a/TUI.Test/StackPanelTests.cs b/TUI.Test/StackPanelTests.cs
index b08469a..4026b07 100644
--- a/TUI.Test/StackPanelTests.cs
+++ b/TUI.Test/StackPanelTests.cs
@@ -569,15 +569,93 @@ public void StackPanelHorizontalChildSpansThePanelHeight()
 	}
 
 	/// <summary>
-	/// Tests that a container that does not use the available width, such as BorderElement, measures
-	/// the same with or without one.
+	/// Tests that a BorderElement passes the width it is measured against down to its child, less
+	/// the border, so word-wrapped text inside it reports a row per wrapped line (ktsu-dev/TUI#161).
 	/// </summary>
 	[TestMethod]
-	public void ContainerWithoutAWidthAwareLayoutMeasuresTheSameWithAWidth()
+	public void BorderElementMeasuresItsChildAgainstTheWidthInsideTheBorder()
 	{
-		BorderElement border = [new TextElement("abc")];
+		BorderElement border = [new TextElement("hello world foo") { WordWrap = true }];
 
-		Assert.AreEqual(border.CalculateRequiredDimensions(), border.CalculateRequiredDimensions(2));
+		Assert.AreEqual(new Dimensions(17, 3), border.CalculateRequiredDimensions());
+		Assert.AreEqual(new Dimensions(11, 4), border.CalculateRequiredDimensions(12));
+	}
+
+	/// <summary>
+	/// Tests that word-wrapped text inside a border inside a vertical panel is given, and draws,
+	/// every wrapped line rather than only the first (ktsu-dev/TUI#161).
+	/// </summary>
+	[TestMethod]
+	public void StackPanelVerticalDrawsEveryWrappedLineOfTextInsideABorder()
+	{
+		TextElement text = new("hello world foo") { WordWrap = true };
+		BorderElement border = [text];
+		StackPanel panel = [border];
+		panel.Dimensions = new Dimensions(12, 10);
+		panel.ArrangeChildren();
+		border.ArrangeChildren();
+
+		RecordingConsoleProvider provider = new();
+		panel.Render(provider);
+
+		Assert.AreEqual(new Dimensions(12, 4), border.Dimensions);
+		Assert.AreEqual(new Dimensions(10, 2), text.Dimensions);
+		Assert.AreEqual(new Position(1, 1), Assert.ContainsSingle(provider.WritesOf("hello")).Position);
+		Assert.AreEqual(new Position(1, 2), Assert.ContainsSingle(provider.WritesOf("world foo")).Position);
+	}
+
+	/// <summary>
+	/// Tests that a horizontal panel measures word-wrapped text against the width it has, so it
+	/// reports the wrapped height to a parent rather than one row (ktsu-dev/TUI#161).
+	/// </summary>
+	[TestMethod]
+	public void StackPanelHorizontalRequiredDimensionsWrapTextToTheAvailableWidth()
+	{
+		StackPanel panel = new() { Orientation = Orientation.Horizontal };
+		panel.Add(new TextElement("hello world foo") { WordWrap = true });
+
+		Assert.AreEqual(new Dimensions(15, 1), panel.CalculateRequiredDimensions());
+		Assert.AreEqual(new Dimensions(5, 3), panel.CalculateRequiredDimensions(8));
+	}
+
+	/// <summary>
+	/// Tests that a horizontal panel measures each child against the width its earlier siblings and
+	/// the spacing leave, as it does when arranging them (ktsu-dev/TUI#161).
+	/// </summary>
+	[TestMethod]
+	public void StackPanelHorizontalMeasuresEachChildAgainstTheRemainingWidth()
+	{
+		StackPanel panel = new() { Orientation = Orientation.Horizontal, Spacing = 1 };
+		panel.Add(new TextElement("abc"));
+		panel.Add(new TextElement("hello world") { WordWrap = true });
+
+		Assert.AreEqual(new Dimensions(9, 2), panel.CalculateRequiredDimensions(9));
+	}
+
+	/// <summary>
+	/// Tests that word-wrapped text inside a horizontal panel inside a vertical panel is given a row
+	/// per wrapped line and draws them all, with the next row placed below it (ktsu-dev/TUI#161).
+	/// </summary>
+	[TestMethod]
+	public void StackPanelVerticalDrawsEveryWrappedLineOfTextInsideAHorizontalPanel()
+	{
+		StackPanel row = new() { Orientation = Orientation.Horizontal };
+		TextElement text = new("hello world foo") { WordWrap = true };
+		row.Add(text);
+		StackPanel panel = [row, new TextElement("next")];
+		panel.Dimensions = new Dimensions(8, 10);
+		panel.ArrangeChildren();
+		row.ArrangeChildren();
+
+		RecordingConsoleProvider provider = new();
+		panel.Render(provider);
+
+		Assert.AreEqual(new Dimensions(8, 3), row.Dimensions);
+		Assert.AreEqual(new Dimensions(5, 3), text.Dimensions);
+		Assert.AreEqual(new Position(0, 0), Assert.ContainsSingle(provider.WritesOf("hello")).Position);
+		Assert.AreEqual(new Position(0, 1), Assert.ContainsSingle(provider.WritesOf("world")).Position);
+		Assert.AreEqual(new Position(0, 2), Assert.ContainsSingle(provider.WritesOf("foo")).Position);
+		Assert.AreEqual(new Position(0, 3), Assert.ContainsSingle(provider.WritesOf("next")).Position);
 	}
 
 	/// <summary>
diff --git a/TUI/Elements/Layouts/StackPanel.cs b/TUI/Elements/Layouts/StackPanel.cs
index 321c565..4a4a666 100644
--- a/TUI/Elements/Layouts/StackPanel.cs
+++ b/TUI/Elements/Layouts/StackPanel.cs
@@ -91,11 +91,12 @@ protected override void OnArrangeChildren()
 		{
 			unplaced.Remove(child);
 
-			// A vertical child's width is known before its height, so it is measured against that
-			// width. Word-wrapped text needs this to report one row per wrapped line (ktsu-dev/TUI#131).
+			// A child is measured against the width it can have: the panel's width when stacking
+			// vertically, and the width not yet taken when stacking horizontally. Word-wrapped text
+			// needs this to report one row per wrapped line (ktsu-dev/TUI#131, ktsu-dev/TUI#161).
 			Dimensions childDimensions = Orientation == Orientation.Vertical
 				? child.CalculateRequiredDimensions(contentArea.Width)
-				: child.CalculateRequiredDimensions();
+				: child.CalculateRequiredDimensions(contentArea.Width - currentOffset);
 
 			if (Orientation == Orientation.Vertical)
 			{
@@ -165,12 +166,18 @@ private Dimensions CalculateRequiredDimensionsForChildren(int? availableWidth)
 
 		IUIElement[] visibleChildren = [.. GetVisibleChildren()];
 		int totalSpacing = Math.Max(0, (visibleChildren.Length - 1) * Spacing);
+		int consumedWidth = 0;
 
 		foreach (IUIElement? child in visibleChildren)
 		{
-			Dimensions childDimensions = Orientation == Orientation.Vertical && availableWidth is int width
-				? child.CalculateRequiredDimensions(width)
-				: child.CalculateRequiredDimensions();
+			// A horizontal child gets the width its earlier siblings and the spacing between them
+			// leave, as it does when arranged (ktsu-dev/TUI#161).
+			Dimensions childDimensions = availableWidth switch
+			{
+				int width when Orientation == Orientation.Vertical => child.CalculateRequiredDimensions(width),
+				int width => child.CalculateRequiredDimensions(Math.Max(0, width - consumedWidth)),
+				_ => child.CalculateRequiredDimensions(),
+			};
 
 			if (Orientation == Orientation.Vertical)
 			{
@@ -180,6 +187,7 @@ private Dimensions CalculateRequiredDimensionsForChildren(int? availableWidth)
 			else
 			{
 				totalWidth += childDimensions.Width;
+				consumedWidth += childDimensions.Width + Spacing;
 				maxHeight = Math.Max(maxHeight, childDimensions.Height);
 			}
 		}
diff --git a/TUI/Elements/Primitives/BorderElement.cs b/TUI/Elements/Primitives/BorderElement.cs
index be27642..f962c25 100644
--- a/TUI/Elements/Primitives/BorderElement.cs
+++ b/TUI/Elements/Primitives/BorderElement.cs
@@ -187,9 +187,18 @@ protected override void OnArrangeChildren()
 	// class adds to this result, so only the child's own size belongs here (ktsu-dev/TUI#132).
 	// A title is drawn as " title " between the corners, so the content area must be at least
 	// two wider than the title or a layout sizes the border too narrow to show it (ktsu-dev/TUI#157).
-	protected override Dimensions OnCalculateRequiredDimensionsForChildren()
+	protected override Dimensions OnCalculateRequiredDimensionsForChildren() =>
+		WithRoomForTitle(Children.Count == 0 ? Dimensions.Empty : Children.First().CalculateRequiredDimensions());
+
+	/// <inheritdoc />
+	// The base class has already taken the border off availableWidth, so the child is measured
+	// against the width it will be arranged into. Without this a word-wrapped child is measured
+	// unwrapped and given a single row (ktsu-dev/TUI#161).
+	protected override Dimensions OnCalculateRequiredDimensionsForChildren(int availableWidth) =>
+		WithRoomForTitle(Children.Count == 0 ? Dimensions.Empty : Children.First().CalculateRequiredDimensions(availableWidth));
+
+	private Dimensions WithRoomForTitle(Dimensions childDimensions)
 	{
-		Dimensions childDimensions = Children.Count == 0 ? Dimensions.Empty : Children.First().CalculateRequiredDimensions();
 		if (BorderStyle == BorderStyle.None || string.IsNullOrEmpty(Title))
 		{
 			return childDimensions;