diff --git a/CHANGES.md b/CHANGES.md
index 74ecef559..7da69b8f2 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -2,6 +2,10 @@
 
 * Add support for the clip-path presentation attribute
 	(#333 by Martin @MBodin Bodin)
+* Add support for Microdata attributes
+  (#343 by toastal)
+* Add support for <meta itemprop> to be in flow content
+  (#343 by toastal)
 
 # 4.6.0
 
diff --git a/lib/html_f.ml b/lib/html_f.ml
index 4e1484f99..4adbfaed2 100644
--- a/lib/html_f.ml
+++ b/lib/html_f.ml
@@ -70,6 +70,8 @@ struct
 
   let uri_attrib a s = Xml.uri_attrib a s
 
+  let uris_attrib a ss = Xml.uris_attrib a ss
+
   let space_sep_attrib = Xml.space_sep_attrib
 
   let comma_sep_attrib = Xml.comma_sep_attrib
@@ -500,6 +502,18 @@ struct
 
   let a_aria name = space_sep_attrib ("aria-" ^ name)
 
+  (* Microdata *)
+
+  let a_itemid = uri_attrib "itemid"
+
+  let a_itemprop = string_attrib "itemprop"
+
+  let a_itemref = space_sep_attrib "itemref"
+
+  let a_itemscope = constant_attrib "itemscope"
+
+  let a_itemtype = uris_attrib "itemtype"
+
   type 'a elt = Xml.elt
 
   type ('a, 'b) nullary = ?a: (('a attrib) list) -> unit -> 'b elt
@@ -817,6 +831,9 @@ struct
 
   let meta = terminal "meta"
 
+  let meta_itemprop itemprop ?(a = []) () =
+    Xml.leaf ~a: ((a_itemprop itemprop) :: a) "meta"
+
   let style ?(a = []) elts = Xml.node ~a "style" elts
 
   let link ~rel ~href ?(a = []) () =
@@ -858,6 +875,8 @@ struct
 
     let uri_attrib a s = Xml.uri_attrib a s
 
+    let uris_attrib a ss = Xml.uris_attrib a ss
+
     let space_sep_attrib = Xml.space_sep_attrib
 
     let comma_sep_attrib = Xml.comma_sep_attrib
diff --git a/lib/html_sigs.mli b/lib/html_sigs.mli
index 1cf169c8f..2bc94102c 100644
--- a/lib/html_sigs.mli
+++ b/lib/html_sigs.mli
@@ -694,6 +694,24 @@ module type T = sig
       @see <https://www.w3.org/TR/wai-aria-1.1/#state_prop_def> List of WAI-ARIA attributes
   *)
 
+  (** {3 Microdata support} *)
+
+  (** {{: https://html.spec.whatwg.org/multipage/microdata.html} Microdata} is
+      a specification written by the W3C, defining a set of additional HTML
+      attributes that can be applied to elements to annotate content with
+      specific machine-readable labels using schemas.
+  *)
+
+  val a_itemid : Xml.uri wrap -> [> | `ItemID ] attrib
+
+  val a_itemprop : string wrap -> [> | `ItemProp ] attrib
+
+  val a_itemref : idrefs wrap -> [> | `ItemRef ] attrib
+
+  val a_itemscope : unit -> [> | `ItemScope ] attrib
+
+  val a_itemtype : Xml.uri list wrap -> [> | `ItemType ] attrib
+
   (** {2:elements Elements} *)
 
   val txt : string wrap -> [> | txt] elt
@@ -1079,6 +1097,10 @@ module type T = sig
 
   val meta : ([< | meta_attrib], [> | meta]) nullary
 
+  val meta_itemprop :
+    string wrap ->
+    ([< | meta_attrib], [> | meta_with_itemprop]) nullary
+
   (** {3 Style Sheets} *)
 
   val style :
@@ -1169,7 +1191,10 @@ module type T = sig
     (** Same, for URI attribute *)
     val uri_attrib : string -> uri wrap -> 'a attrib
 
-    (** Same, for a space separated list of values *)
+    (** Same, for a space-separated list of URI attributes *)
+    val uris_attrib : string -> uri list wrap -> 'a attrib
+
+    (** Same, for a space-separated list of values *)
     val space_sep_attrib : string -> string list wrap -> 'a attrib
 
     (** Same, for a comma separated list of values *)
diff --git a/lib/html_types.mli b/lib/html_types.mli
index 7ccd3d3cc..8e6ec1207 100644
--- a/lib/html_types.mli
+++ b/lib/html_types.mli
@@ -380,8 +380,19 @@ type aria =
     | `Aria
   ]
 
+(** {2 Microdata} *)
+
+type microdata =
+  [
+    | `ItemID
+    | `ItemProp
+    | `ItemRef
+    | `ItemScope
+    | `ItemType
+  ]
+
 (** Common attributes *)
-type common = [ | core | i18n | events | aria ]
+type common = [ | core | i18n | events | aria | microdata ]
 
 (** {1 Categories of HTML elements}
 
@@ -571,6 +582,7 @@ type core_phrasing =
     | `Img | `Img_interactive
     | `Picture
     | `PCDATA
+    | `Meta_with_itemprop
   ]
 
 type core_phrasing_without_noscript =
@@ -611,6 +623,7 @@ type core_phrasing_without_noscript =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
   ]
 type core_phrasing_without_interactive =
   [
@@ -646,6 +659,7 @@ type core_phrasing_without_interactive =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
   ]
 
 type core_phrasing_without_media =
@@ -686,6 +700,7 @@ type core_phrasing_without_media =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
   ]
 
 type phrasing_without_noscript =
@@ -722,9 +737,10 @@ type (+'a, +'b) between_phrasing_and_phrasing_without_interactive =
                                            phrasing,
                                            phrasing_without_media) transparent
         > `Abbr `B `Bdo `Br `Canvas `Cite `Code `Command
-        `Datalist `Del `Dfn `Em `I `Img `Picture `Ins `Kbd `Map `Mark `Meter
-        `Noscript `Object `PCDATA `Progress `Q `Ruby `Samp `Script
-        `Small `Span `Strong `Sub `Sup `Svg `Template `Time `U `Var `Wbr ] as 'a)
+        `Datalist `Del `Dfn `Em `I `Img `Picture `Ins `Kbd `Map `Mark 
+        `Meta_with_itemprop `Meter `Noscript `Object `PCDATA `Progress `Q `Ruby 
+        `Samp `Script `Small `Span `Strong `Sub `Sup `Svg `Template `Time `U 
+        `Var `Wbr ] as 'a)
 
 (** Phrasing without the interactive markups *)
 type phrasing_without_dfn =
@@ -761,6 +777,7 @@ type phrasing_without_dfn =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
     | (phrasing_without_interactive, phrasing_without_noscript,
        phrasing_without_dfn, phrasing_without_media) transparent
   ]
@@ -799,6 +816,7 @@ type phrasing_without_label =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
     | (phrasing_without_interactive, phrasing_without_noscript,
        phrasing_without_label, phrasing_without_media) transparent
   ]
@@ -840,6 +858,7 @@ type phrasing_without_progress =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
     | (phrasing_without_interactive, phrasing_without_noscript,
        phrasing_without_progress, phrasing_without_media) transparent
   ]
@@ -878,6 +897,7 @@ type phrasing_without_time =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
     | (phrasing_without_interactive, phrasing_without_noscript,
        phrasing_without_time, phrasing_without_media) transparent
   ]
@@ -919,6 +939,7 @@ type phrasing_without_meter =
     | `B
     | `Abbr
     | `PCDATA
+    | `Meta_with_itemprop
     | (phrasing_without_interactive, phrasing_without_noscript,
        phrasing_without_meter, phrasing_without_media) transparent
   ]
@@ -2276,6 +2297,8 @@ type noscript_attrib = [ | common ]
 (* NAME: meta, KIND: nullary, TYPE: [= common | `Http_equiv | `Name | `Content | `Charset ], [=`Meta], ARG: notag, ATTRIB:  OUT: [=`Meta] *)
 type meta = [ | `Meta ]
 
+type meta_with_itemprop = [ | `Meta_with_itemprop ]
+
 type meta_content = notag
 
 type meta_content_fun = notag
diff --git a/syntax/reflect/reflect.ml b/syntax/reflect/reflect.ml
index dafd1975b..7274105be 100644
--- a/syntax/reflect/reflect.ml
+++ b/syntax/reflect/reflect.ml
@@ -174,6 +174,7 @@ let rec to_attribute_parser lang name ~loc = function
   | [[%type: shape]] ->
     [%expr variant]
 
+  | [[%type: Xml.uri list]]
   | [[%type: nmtokens]]
   | [[%type: idrefs]]
   | [[%type: charsets]]
diff --git a/test/test_ppx.ml b/test/test_ppx.ml
index b521aada4..6de07ee8f 100644
--- a/test/test_ppx.ml
+++ b/test/test_ppx.ml
@@ -303,6 +303,26 @@ let attribs = "ppx attribs", HtmlTests.make Html.[
   [[%html "<div aria-hidden=true></div>"]],
   [div ~a:[a_aria "hidden" ["true"]] []] ;
 
+  "microdata attributes",
+  [[%html "<dl itemscope itemtype='https://md.example.com/track https://md.example.com/lighting'><dt>Name</dt><dd itemprop='name'>Turnout Lantern Kit</dd><dt>Purpose<dd>For retrofitting 2 <span itemprop='track-type'>C</span> Track turnouts.<meta itemprop='scale' content='HO'></dl>"]],
+  [dl
+    ~a: [
+      a_itemscope ();
+      a_itemtype ["https://md.example.com/track"; "https://md.example.com/lighting"];
+    ]
+    [
+      dt [txt "Name"];
+      dd ~a: [a_itemprop "name"] [txt "Turnout Lantern Kit"];
+      dt [txt "Purpose"];
+      dd
+        [
+          txt "For retrofitting 2 ";
+          span ~a: [a_itemprop "track-type"] [txt "C"];
+          txt " Track turnouts.";
+          meta_itemprop "scale" ~a: [a_content "HO"] ();
+        ]
+  ]];
+
   "touch events",
   [[%html "<div ontouchstart='alert()'></div>"]],
   [div ~a:[a_ontouchstart "alert()"] []] ;