diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index ee892b75f11..e4aa4a9d573 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -1547,31 +1547,29 @@ impl Fragment {
             }
         };
 
-        // Take borders and padding for parent inline fragments into account, if necessary.
-        if self.is_primary_fragment() {
-            let writing_mode = self.style.writing_mode;
-            if let Some(ref context) = self.inline_context {
-                for node in &context.nodes {
-                    let mut border_width = node.style.logical_border_width();
-                    let mut padding = model::padding_from_style(&*node.style, Au(0), writing_mode);
-                    let mut margin = model::specified_margin_from_style(&*node.style, writing_mode);
-                    if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
-                        border_width.inline_start = Au(0);
-                        padding.inline_start = Au(0);
-                        margin.inline_start = Au(0);
-                    }
-                    if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
-                        border_width.inline_end = Au(0);
-                        padding.inline_end = Au(0);
-                        margin.inline_end = Au(0);
-                    }
-
-                    result.surrounding_size =
-                        result.surrounding_size +
-                        border_width.inline_start_end() +
-                        padding.inline_start_end() +
-                        margin.inline_start_end();
+        // Take borders and padding for parent inline fragments into account.
+        let writing_mode = self.style.writing_mode;
+        if let Some(ref context) = self.inline_context {
+            for node in &context.nodes {
+                let mut border_width = node.style.logical_border_width();
+                let mut padding = model::padding_from_style(&*node.style, Au(0), writing_mode);
+                let mut margin = model::specified_margin_from_style(&*node.style, writing_mode);
+                if !node.flags.contains(FIRST_FRAGMENT_OF_ELEMENT) {
+                    border_width.inline_start = Au(0);
+                    padding.inline_start = Au(0);
+                    margin.inline_start = Au(0);
                 }
+                if !node.flags.contains(LAST_FRAGMENT_OF_ELEMENT) {
+                    border_width.inline_end = Au(0);
+                    padding.inline_end = Au(0);
+                    margin.inline_end = Au(0);
+                }
+
+                result.surrounding_size =
+                    result.surrounding_size +
+                    border_width.inline_start_end() +
+                    padding.inline_start_end() +
+                    margin.inline_start_end();
             }
         }
 
diff --git a/tests/wpt/mozilla/meta/MANIFEST.json b/tests/wpt/mozilla/meta/MANIFEST.json
index ee5039c9883..7fa8ec32df4 100644
--- a/tests/wpt/mozilla/meta/MANIFEST.json
+++ b/tests/wpt/mozilla/meta/MANIFEST.json
@@ -2699,6 +2699,18 @@
      {}
     ]
    ],
+   "css/inline_block_nested_margin.html": [
+    [
+     "/_mozilla/css/inline_block_nested_margin.html",
+     [
+      [
+       "/_mozilla/css/inline_block_nested_margin_ref.html",
+       "=="
+      ]
+     ],
+     {}
+    ]
+   ],
    "css/inline_block_opacity_change.html": [
     [
      "/_mozilla/css/inline_block_opacity_change.html",
@@ -7939,6 +7951,11 @@
      {}
     ]
    ],
+   "css/inline_block_nested_margin_ref.html": [
+    [
+     {}
+    ]
+   ],
    "css/inline_block_opacity_change_ref.html": [
     [
      {}
@@ -21886,6 +21903,14 @@
    "ed6e0f503cb26c1091270ed0992a0a41553846d9",
    "support"
   ],
+  "css/inline_block_nested_margin.html": [
+   "b4114aa6421b4c9117e60e66ccc09868e05f3239",
+   "reftest"
+  ],
+  "css/inline_block_nested_margin_ref.html": [
+   "5e00c77f55a3d12e841e9c99395f4d3783664fd8",
+   "support"
+  ],
   "css/inline_block_opacity_change.html": [
    "df6b37b744fdf79da9d33c54b8ce77abd462c53b",
    "reftest"
diff --git a/tests/wpt/mozilla/tests/css/inline_block_nested_margin.html b/tests/wpt/mozilla/tests/css/inline_block_nested_margin.html
new file mode 100644
index 00000000000..addb612bb97
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/inline_block_nested_margin.html
@@ -0,0 +1,15 @@
+<!doctype html>
+<meta charset="utf-8">
+<link rel="match" href="inline_block_nested_margin_ref.html">
+<style>
+ #outer {
+     margin: 0 50px;
+ }
+ #inner {
+     display: inline-block;
+     width: 200px;
+     height: 40px;
+     background: orange;
+ }
+</style>
+<span id="outer"><span id="inner"></span></span>
diff --git a/tests/wpt/mozilla/tests/css/inline_block_nested_margin_ref.html b/tests/wpt/mozilla/tests/css/inline_block_nested_margin_ref.html
new file mode 100644
index 00000000000..296d91994ac
--- /dev/null
+++ b/tests/wpt/mozilla/tests/css/inline_block_nested_margin_ref.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<meta charset="utf-8">
+<style>
+ #inner {
+     display: inline-block;
+     width: 200px;
+     height: 40px;
+     background: orange;
+     margin: 0 50px;
+ }
+</style>
+<span id="inner"></span>