diff --git a/CHANGES.md b/CHANGES.md
index 07978e7bcc..ebc43ce2f3 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -22,6 +22,7 @@ Tags:
 - Add a tooltip to references with text (@Julow, #945)
 - Add emoji to alerts in CSS (@yawaramin, #928)
 - Add common language in shipped highlightjs (@Julow, #953)
+- Display 'private' keyword for private type extensions (@gpetiot, #1019)
 
 ### Fixed
 - Fix `--hidden` not always taken into account (@panglesd, #940)
diff --git a/src/document/generator.ml b/src/document/generator.ml
index b04e92bf42..fde317badc 100644
--- a/src/document/generator.ml
+++ b/src/document/generator.ml
@@ -646,6 +646,9 @@ module Make (Syntax : SYNTAX) = struct
         O.keyword "type" ++ O.txt " "
         ++ Link.from_path (t.type_path :> Paths.Path.t)
         ++ O.txt " +=" ++ O.sp
+        ++
+        if t.private_ then O.keyword Syntax.Type.private_keyword ++ O.sp
+        else O.noop
       in
       let content =
         O.documentedSrc prefix
diff --git a/test/generators/html/Ocamlary.html b/test/generators/html/Ocamlary.html
index de6bda5626..8b0dbcad68 100644
--- a/test/generators/html/Ocamlary.html
+++ b/test/generators/html/Ocamlary.html
@@ -1863,7 +1863,8 @@ <h4 id="advanced-type-stuff">
     <div class="spec type extension anchored" id="extension-decl-ExtF">
      <a href="#extension-decl-ExtF" class="anchor"></a>
      <code>
-      <span><span class="keyword">type</span> <a href="#type-ext">ext</a> += 
+      <span><span class="keyword">type</span> <a href="#type-ext">ext</a>
+        += <span class="keyword">private</span> 
       </span>
      </code>
      <ol>
diff --git a/test/generators/latex/Ocamlary.tex b/test/generators/latex/Ocamlary.tex
index fd03953742..439831fff2 100644
--- a/test/generators/latex/Ocamlary.tex
+++ b/test/generators/latex/Ocamlary.tex
@@ -572,7 +572,7 @@ \subsubsection{Advanced Type Stuff\label{advanced-type-stuff}}%
 \begin{ocamltabular}{p{1.000\textwidth}}\ocamlcodefragment{| \ocamltag{extension}{ExtE}}\label{module-Ocamlary-extension-ExtE}\\
 \end{ocamltabular}%
 \\
-\label{module-Ocamlary-extension-decl-ExtF}\ocamlcodefragment{\ocamltag{keyword}{type} \hyperref[module-Ocamlary-type-ext]{\ocamlinlinecode{ext}} += }\\
+\label{module-Ocamlary-extension-decl-ExtF}\ocamlcodefragment{\ocamltag{keyword}{type} \hyperref[module-Ocamlary-type-ext]{\ocamlinlinecode{ext}} += \ocamltag{keyword}{private} }\\
 \begin{ocamltabular}{p{1.000\textwidth}}\ocamlcodefragment{| \ocamltag{extension}{ExtF}}\label{module-Ocamlary-extension-ExtF}\\
 \end{ocamltabular}%
 \\
diff --git a/test/generators/man/Ocamlary.3o b/test/generators/man/Ocamlary.3o
index f2ab4c7dc3..b9ca36361e 100644
--- a/test/generators/man/Ocamlary.3o
+++ b/test/generators/man/Ocamlary.3o
@@ -1515,7 +1515,7 @@ A mystery wrapped in an ellipsis
 | \f[CB]ExtE\fR
 .br 
 .sp 
-\f[CB]type\fR ext += 
+\f[CB]type\fR ext += \f[CB]private\fR 
 .br 
 .ti +2
 | \f[CB]ExtF\fR