diff --git a/LayoutTests/fast/flexbox/overlapped-form-controls-expected.html b/LayoutTests/fast/flexbox/overlapped-form-controls-expected.html
new file mode 100644
index 000000000000..4a392701b184
--- /dev/null
+++ b/LayoutTests/fast/flexbox/overlapped-form-controls-expected.html
@@ -0,0 +1,10 @@
+<style>
+div {
+  position: absolute;
+}
+input {
+  outline: solid 1px black;
+}
+</style>
+<div><input type="checkbox"></div>
+<div style="top: 100px;"><input type="radio"></div>
\ No newline at end of file
diff --git a/LayoutTests/fast/flexbox/overlapped-form-controls.html b/LayoutTests/fast/flexbox/overlapped-form-controls.html
new file mode 100644
index 000000000000..39348f581610
--- /dev/null
+++ b/LayoutTests/fast/flexbox/overlapped-form-controls.html
@@ -0,0 +1,15 @@
+<style>
+div {
+  max-width: 30px;
+  display: flex;
+  color: transparent;
+  font-family: Ahem;
+  font-size: 10px;
+  position: absolute;
+}
+input {
+  outline: solid 1px black;
+}
+</style>
+<div><input type="checkbox">PASS if form control is not overlapped.</div>
+<div style="top: 100px;"><input type="radio">PASS if form control is not overlapped.</div>
diff --git a/LayoutTests/platform/ios-wk2/imported/w3c/web-platform-tests/css/css-flexbox/radiobutton-min-size-expected.txt b/LayoutTests/platform/ios-wk2/imported/w3c/web-platform-tests/css/css-flexbox/radiobutton-min-size-expected.txt
deleted file mode 100644
index 3d1950f9ac34..000000000000
--- a/LayoutTests/platform/ios-wk2/imported/w3c/web-platform-tests/css/css-flexbox/radiobutton-min-size-expected.txt
+++ /dev/null
@@ -1,8 +0,0 @@
-You should see two identical-looking lines, both with a radio button at the beginning.
-
-
-Text
-Text
-
-FAIL two radio button widths are identical assert_equals: width should be equal expected 0 but got 16
-
diff --git a/Source/WebCore/platform/Theme.cpp b/Source/WebCore/platform/Theme.cpp
index 7b709e5caf39..a119a60d53f6 100644
--- a/Source/WebCore/platform/Theme.cpp
+++ b/Source/WebCore/platform/Theme.cpp
@@ -51,7 +51,8 @@ LengthSize Theme::controlSize(StyleAppearance, const FontCascade&, const LengthS
 LengthSize Theme::minimumControlSize(StyleAppearance appearance, const FontCascade& fontCascade, const LengthSize& zoomedSize, const LengthSize& nonShrinkableZoomedSize, float zoom) const
 {
     auto minSize = minimumControlSize(appearance, fontCascade, zoomedSize, zoom);
-    if (appearance == StyleAppearance::Radio) {
+    // Other StyleAppearance types are composed controls with shadow subtree.
+    if (appearance == StyleAppearance::Radio || appearance == StyleAppearance::Checkbox) {
         if (zoomedSize.width.isIntrinsicOrAuto())
             minSize.width = nonShrinkableZoomedSize.width;
         if (zoomedSize.height.isIntrinsicOrAuto())
diff --git a/Source/WebCore/rendering/RenderThemeIOS.h b/Source/WebCore/rendering/RenderThemeIOS.h
index 5e500f92856d..78d0f7b4a100 100644
--- a/Source/WebCore/rendering/RenderThemeIOS.h
+++ b/Source/WebCore/rendering/RenderThemeIOS.h
@@ -204,6 +204,7 @@ class RenderThemeIOS final : public RenderThemeCocoa {
     Color controlTintColor(const RenderStyle&, OptionSet<StyleColorOptions>) const;
 
     void adjustStyleForAlternateFormControlDesignTransition(RenderStyle&, const Element*) const;
+    void adjustMinimumIntrinsicSizeForAppearance(StyleAppearance, RenderStyle&) const;
 };
 
 }
diff --git a/Source/WebCore/rendering/RenderThemeIOS.mm b/Source/WebCore/rendering/RenderThemeIOS.mm
index ecdf390a5dbe..9304f572da86 100644
--- a/Source/WebCore/rendering/RenderThemeIOS.mm
+++ b/Source/WebCore/rendering/RenderThemeIOS.mm
@@ -342,6 +342,7 @@ static IOSGradientRef gradientWithName(IOSGradientType gradientType)
 void RenderThemeIOS::adjustCheckboxStyle(RenderStyle& style, const Element* element) const
 {
     adjustStyleForAlternateFormControlDesignTransition(style, element);
+    adjustMinimumIntrinsicSizeForAppearance(StyleAppearance::Checkbox, style);
 
     if (!style.width().isIntrinsicOrAuto() && !style.height().isAuto())
         return;
@@ -488,9 +489,19 @@ static void drawJoinedLines(CGContextRef context, const Vector<CGPoint>& points,
     return RenderTheme::isControlStyled(style, userAgentStyle);
 }
 
+void RenderThemeIOS::adjustMinimumIntrinsicSizeForAppearance(StyleAppearance appearance, RenderStyle& style) const
+{
+    auto minControlSize = Theme::singleton().minimumControlSize(appearance, style.fontCascade(), { style.minWidth(), style.minHeight() }, { style.width(), style.height() }, style.effectiveZoom());
+    if (minControlSize.width.value() > style.minWidth().value())
+        style.setMinWidth(WTFMove(minControlSize.width));
+    if (minControlSize.height.value() > style.minHeight().value())
+        style.setMinHeight(WTFMove(minControlSize.height));
+}
+
 void RenderThemeIOS::adjustRadioStyle(RenderStyle& style, const Element* element) const
 {
     adjustStyleForAlternateFormControlDesignTransition(style, element);
+    adjustMinimumIntrinsicSizeForAppearance(StyleAppearance::Radio, style);
 
     if (!style.width().isIntrinsicOrAuto() && !style.height().isAuto())
         return;