diff --git a/CHANGES.md b/CHANGES.md
index 3490684715..5adb988a3e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -63,6 +63,7 @@
 * Ppx: allow "function" in object literals (#1897)
 * Lib: add Dom_html.window.matchMedia & Dom_html.mediaQueryList (#2017)
 * Lib: make the Wasm version of Json.output work with native ints and JavaScript objects (#1872)
+* Lib: add Intl.RelativeDateFormat (#2070)
 
 ## Bug fixes
 * Compiler: fix stack overflow issues with double translation (#1869)
diff --git a/lib/js_of_ocaml/intl.ml b/lib/js_of_ocaml/intl.ml
index 6a71b5d2cb..c659db4cc1 100644
--- a/lib/js_of_ocaml/intl.ml
+++ b/lib/js_of_ocaml/intl.ml
@@ -413,6 +413,57 @@ module PluralRules = struct
   end
 end
 
+module RelativeTimeFormat = struct
+  include Shared
+
+  class type resolved_options = object
+    method locale : Js.js_string Js.t Js.readonly_prop
+
+    method style : Js.js_string Js.t Js.readonly_prop
+
+    method numberingSystem : Js.js_string Js.t Js.readonly_prop
+
+    method numeric : Js.js_string Js.t Js.readonly_prop
+  end
+
+  class type options = object
+    method localeMatcher : Js.js_string Js.t Js.prop
+
+    method numberingSystem : Js.js_string Js.t Js.optdef Js.prop
+
+    method style : Js.js_string Js.t Js.optdef Js.prop
+
+    method numeric : Js.js_string Js.t Js.optdef Js.prop
+  end
+
+  let options () : options Js.t =
+    object%js
+      val mutable localeMatcher = Js.string "best fit"
+
+      val mutable style = Js.undefined
+
+      val mutable numberingSystem = Js.undefined
+
+      val mutable numeric = Js.undefined
+    end
+
+  class type format_part = object
+    method _type : Js.js_string Js.t Js.readonly_prop
+
+    method _value : Js.js_string Js.t Js.readonly_prop
+  end
+
+  class type t = object
+    method format :
+      (Js.number Js.t -> Js.js_string Js.t -> Js.js_string Js.t) Js.readonly_prop
+
+    method formatToParts :
+      Js.date Js.t Js.optdef -> format_part Js.t Js.js_array Js.t Js.meth
+
+    method resolvedOptions : unit -> resolved_options Js.t Js.meth
+  end
+end
+
 class type intl = object
   method _Collator : Collator._object Js.t Js.readonly_prop
 
@@ -422,6 +473,8 @@ class type intl = object
 
   method _PluralRules : PluralRules._object Js.t Js.readonly_prop
 
+  method _RelativeTimeFormat : RelativeTimeFormat._object Js.t Js.readonly_prop
+
   method getCanonicalLocales :
     Js.js_string Js.t Js.js_array Js.t -> Js.js_string Js.t Js.js_array Js.t Js.meth
 end
@@ -436,4 +489,6 @@ let numberFormat_constr = Js.Unsafe.global##._Intl##._NumberFormat
 
 let pluralRules_constr = Js.Unsafe.global##._Intl##._PluralRules
 
+let relativeTimeFormat_constr = Js.Unsafe.global##._Intl##._RelativeTimeFormat
+
 let is_supported () = Js.Optdef.test intl
diff --git a/lib/js_of_ocaml/intl.mli b/lib/js_of_ocaml/intl.mli
index c0e61b9515..066e53312f 100644
--- a/lib/js_of_ocaml/intl.mli
+++ b/lib/js_of_ocaml/intl.mli
@@ -349,6 +349,13 @@ then (
   with Error err -> Console.console##debug (string (string_of_error err)))
 else Console.console##debug (string "Intl is not supported!")
 ]}
+
+    let options = Intl.RelativeTimeFormat.options () in
+    let () = options##.numeric := "auto" in
+    let () = options##.style := "short" in
+    let th_rtf = new%js Intl.relativeTimeFormat_constr (def (jas [| "th-TH" |])) options in
+    fc (th_rtf.format -1 "day");
+
     @see <https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl> for API documentation.
     @see <https://www.ecma-international.org/ecma-402/1.0/> for the ECMAScript specification. *)
 
@@ -627,6 +634,48 @@ module PluralRules : sig
   end
 end
 
+module RelativeTimeFormat : sig
+  include Shared
+
+  class type resolved_options = object
+    method locale : Js.js_string Js.t Js.readonly_prop
+
+    method style : Js.js_string Js.t Js.readonly_prop
+
+    method numberingSystem : Js.js_string Js.t Js.readonly_prop
+
+    method numeric : Js.js_string Js.t Js.readonly_prop
+  end
+
+  class type options = object
+    method localeMatcher : Js.js_string Js.t Js.prop
+
+    method numberingSystem : Js.js_string Js.t Js.optdef Js.prop
+
+    method style : Js.js_string Js.t Js.optdef Js.prop
+
+    method numeric : Js.js_string Js.t Js.optdef Js.prop
+  end
+
+  val options : unit -> options Js.t
+
+  class type format_part = object
+    method _type : Js.js_string Js.t Js.readonly_prop
+
+    method _value : Js.js_string Js.t Js.readonly_prop
+  end
+
+  class type t = object
+    method format :
+      (Js.number Js.t -> Js.js_string Js.t -> Js.js_string Js.t) Js.readonly_prop
+
+    method formatToParts :
+      Js.date Js.t Js.optdef -> format_part Js.t Js.js_array Js.t Js.meth
+
+    method resolvedOptions : unit -> resolved_options Js.t Js.meth
+  end
+end
+
 class type intl = object
   method _Collator : Collator._object Js.t Js.readonly_prop
 
@@ -636,6 +685,8 @@ class type intl = object
 
   method _PluralRules : PluralRules._object Js.t Js.readonly_prop
 
+  method _RelativeTimeFormat : RelativeTimeFormat._object Js.t Js.readonly_prop
+
   method getCanonicalLocales :
     Js.js_string Js.t Js.js_array Js.t -> Js.js_string Js.t Js.js_array Js.t Js.meth
 end
@@ -666,4 +717,10 @@ val pluralRules_constr :
    -> PluralRules.t Js.t)
   Js.constr
 
+val relativeTimeFormat_constr :
+  (   Js.js_string Js.t Js.js_array Js.t Js.optdef
+   -> RelativeTimeFormat.options Js.t Js.optdef
+   -> RelativeTimeFormat.t Js.t)
+  Js.constr
+
 val is_supported : unit -> bool