diff --git a/components/script/dom/htmloptionelement.rs b/components/script/dom/htmloptionelement.rs
index 132de2335b2..79f710db1d2 100644
--- a/components/script/dom/htmloptionelement.rs
+++ b/components/script/dom/htmloptionelement.rs
@@ -17,11 +17,18 @@ use dom::eventtarget::{EventTarget, EventTargetTypeId};
 use dom::htmlelement::{HTMLElement, HTMLElementTypeId};
 use dom::node::{Node, NodeTypeId};
 use dom::virtualmethods::VirtualMethods;
+use std::cell::Cell;
 use util::str::{DOMString, split_html_space_chars};
 
 #[dom_struct]
 pub struct HTMLOptionElement {
-    htmlelement: HTMLElement
+    htmlelement: HTMLElement,
+
+    /// https://html.spec.whatwg.org/multipage/#attr-option-selected
+    selectedness: Cell<bool>,
+
+    /// https://html.spec.whatwg.org/multipage/#concept-option-dirtiness
+    dirtiness: Cell<bool>,
 }
 
 impl HTMLOptionElementDerived for EventTarget {
@@ -38,7 +45,9 @@ impl HTMLOptionElement {
                      document: &Document) -> HTMLOptionElement {
         HTMLOptionElement {
             htmlelement:
-                HTMLElement::new_inherited(HTMLElementTypeId::HTMLOptionElement, localName, prefix, document)
+                HTMLElement::new_inherited(HTMLElementTypeId::HTMLOptionElement, localName, prefix, document),
+            selectedness: Cell::new(false),
+            dirtiness: Cell::new(false),
         }
     }
 
@@ -122,6 +131,23 @@ impl HTMLOptionElementMethods for HTMLOptionElement {
     // https://html.spec.whatwg.org/multipage/#attr-option-label
     make_setter!(SetLabel, "label");
 
+    // https://html.spec.whatwg.org/multipage/#dom-option-defaultselected
+    make_bool_getter!(DefaultSelected, "selected");
+
+    // https://html.spec.whatwg.org/multipage/#dom-option-defaultselected
+    make_bool_setter!(SetDefaultSelected, "selected");
+
+    // https://html.spec.whatwg.org/multipage/#dom-option-selected
+    fn Selected(&self) -> bool {
+        self.selectedness.get()
+    }
+
+    // https://html.spec.whatwg.org/multipage/#dom-option-selected
+    fn SetSelected(&self, selected: bool) {
+        self.dirtiness.set(true);
+        self.selectedness.set(selected);
+        // FIXME: as per the spec, implement 'ask for a reset'
+    }
 }
 
 impl VirtualMethods for HTMLOptionElement {
@@ -147,6 +173,22 @@ impl VirtualMethods for HTMLOptionElement {
                     }
                 }
             },
+            &atom!(selected) => {
+                match mutation {
+                    AttributeMutation::Set(_) => {
+                        // https://html.spec.whatwg.org/multipage/#concept-option-selectedness
+                        if !self.dirtiness.get() {
+                            self.selectedness.set(true);
+                        }
+                    },
+                    AttributeMutation::Removed => {
+                        // https://html.spec.whatwg.org/multipage/#concept-option-selectedness
+                        if !self.dirtiness.get() {
+                            self.selectedness.set(false);
+                        }
+                    },
+                }
+            },
             _ => {},
         }
     }
diff --git a/components/script/dom/webidls/HTMLOptionElement.webidl b/components/script/dom/webidls/HTMLOptionElement.webidl
index c4f57ab4963..b4e3bdac353 100644
--- a/components/script/dom/webidls/HTMLOptionElement.webidl
+++ b/components/script/dom/webidls/HTMLOptionElement.webidl
@@ -11,8 +11,8 @@ interface HTMLOptionElement : HTMLElement {
              attribute boolean disabled;
   //readonly attribute HTMLFormElement? form;
              attribute DOMString label;
-  //         attribute boolean defaultSelected;
-  //         attribute boolean selected;
+             attribute boolean defaultSelected;
+             attribute boolean selected;
              attribute DOMString value;
 
              attribute DOMString text;
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 86cfdccb8fa..f291aeae279 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -17351,6 +17351,10 @@
         "path": "html/semantics/forms/the-option-element/option-label.html",
         "url": "/html/semantics/forms/the-option-element/option-label.html"
       },
+      {
+        "path": "html/semantics/forms/the-option-element/option-selected.html",
+        "url": "/html/semantics/forms/the-option-element/option-selected.html"
+      },
       {
         "path": "html/semantics/forms/the-option-element/option-text-backslash.html",
         "url": "/html/semantics/forms/the-option-element/option-text-backslash.html"
diff --git a/tests/wpt/metadata/html/dom/interfaces.html.ini b/tests/wpt/metadata/html/dom/interfaces.html.ini
index 22905a21630..b453290048c 100644
--- a/tests/wpt/metadata/html/dom/interfaces.html.ini
+++ b/tests/wpt/metadata/html/dom/interfaces.html.ini
@@ -5520,24 +5520,12 @@
   [HTMLOptionElement interface: attribute form]
     expected: FAIL
 
-  [HTMLOptionElement interface: attribute defaultSelected]
-    expected: FAIL
-
-  [HTMLOptionElement interface: attribute selected]
-    expected: FAIL
-
   [HTMLOptionElement interface: attribute index]
     expected: FAIL
 
   [HTMLOptionElement interface: document.createElement("option") must inherit property "form" with the proper type (1)]
     expected: FAIL
 
-  [HTMLOptionElement interface: document.createElement("option") must inherit property "defaultSelected" with the proper type (3)]
-    expected: FAIL
-
-  [HTMLOptionElement interface: document.createElement("option") must inherit property "selected" with the proper type (4)]
-    expected: FAIL
-
   [HTMLOptionElement interface: document.createElement("option") must inherit property "index" with the proper type (7)]
     expected: FAIL
 
diff --git a/tests/wpt/metadata/html/dom/reflection-forms.html.ini b/tests/wpt/metadata/html/dom/reflection-forms.html.ini
index 2e22a912497..851591ec145 100644
--- a/tests/wpt/metadata/html/dom/reflection-forms.html.ini
+++ b/tests/wpt/metadata/html/dom/reflection-forms.html.ini
@@ -10542,114 +10542,6 @@
   [option.tabIndex: IDL set to -2147483648 followed by getAttribute()]
     expected: FAIL
 
-  [option.defaultSelected (<option selected>): typeof IDL attribute]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL get with DOM attribute unset]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to "" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to " foo " followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to undefined followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to null followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to 7 followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to 1.5 followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to true followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to false followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to object "[object Object\]" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to NaN followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to Infinity followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to -Infinity followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to "\\0" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to object "test-toString" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to object "test-valueOf" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): setAttribute() to "selected" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to "" followed by hasAttribute()]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to "" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to " foo " followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to undefined followed by hasAttribute()]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to undefined followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to null followed by hasAttribute()]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to null followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to 7 followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to 1.5 followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to false followed by hasAttribute()]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to object "[object Object\]" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to NaN followed by hasAttribute()]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to NaN followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to Infinity followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to -Infinity followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to "\\0" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to object "test-toString" followed by IDL get]
-    expected: FAIL
-
-  [option.defaultSelected (<option selected>): IDL set to object "test-valueOf" followed by IDL get]
-    expected: FAIL
-
   [option.itemScope: typeof IDL attribute]
     expected: FAIL
 
diff --git a/tests/wpt/web-platform-tests/html/semantics/forms/the-option-element/option-selected.html b/tests/wpt/web-platform-tests/html/semantics/forms/the-option-element/option-selected.html
new file mode 100644
index 00000000000..0a9977a62f8
--- /dev/null
+++ b/tests/wpt/web-platform-tests/html/semantics/forms/the-option-element/option-selected.html
@@ -0,0 +1,61 @@
+<!doctype html>
+<meta charset=utf-8>
+<title>HTMLOptionElement.selected</title>
+<link rel=author title="Corey Farwell" href="mailto:coreyf@rwell.org">
+<link rel=help href="https://html.spec.whatwg.org/multipage/forms.html#dom-option-selected">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<div id=log></div>
+
+<script>
+test(function () {
+  var elem = document.createElement("option");
+  assert_equals(elem.selected, false);
+
+  elem.setAttribute("selected", "");
+  assert_equals(elem.selected, true);
+
+  elem.removeAttribute("selected");
+  assert_equals(elem.selected, false);
+
+  elem.defaultSelected = true
+  assert_equals(elem.selected, true);
+
+  elem.defaultSelected = false;
+  assert_equals(elem.selected, false);
+}, "not dirty");
+
+test(function () {
+  testDirty(true);
+}, "dirty, selected");
+
+test(function () {
+  testDirty(false);
+}, "dirty, not selected");
+
+function testDirty(isSelected) {
+  var elem = document.createElement("option");
+
+  elem.selected = isSelected;  // After this assignment, dirtiness=true
+  assertDirty(elem, isSelected);
+
+  elem.selected = !isSelected;  // Change the value, still dirty
+  assertDirty(elem, !isSelected);
+};
+
+function assertDirty(elem, expect) {
+  assert_equals(elem.selected, expect);
+
+  elem.setAttribute("selected", "");
+  assert_equals(elem.selected, expect);
+
+  elem.removeAttribute("selected");
+  assert_equals(elem.selected, expect);
+
+  elem.defaultSelected = true;
+  assert_equals(elem.selected, expect);
+
+  elem.defaultSelected = false;
+  assert_equals(elem.selected, expect);
+}
+</script>