diff --git a/src/dune_rules/odoc.ml b/src/dune_rules/odoc.ml
index 5fe86196f78b..81f100c3647f 100644
--- a/src/dune_rules/odoc.ml
+++ b/src/dune_rules/odoc.ml
@@ -187,9 +187,18 @@ end = struct
   let odoc_input t = t
 end
 
-let odoc sctx =
+let run_odoc sctx =
   let dir = (Super_context.context sctx).build_dir in
-  SC.resolve_program sctx ~dir "odoc" ~loc:None ~hint:"opam install odoc"
+  let open Memo.O in
+  let+ program =
+    SC.resolve_program sctx ~dir "odoc" ~loc:None ~hint:"opam install odoc"
+  in
+  let deps = Action_builder.env_var "ODOC_SYNTAX" in
+  let run ~dir args =
+    let open Action_builder.With_targets.O in
+    Action_builder.with_no_targets deps >>> Command.run ~dir program args
+  in
+  run
 
 let odoc_base_flags sctx build_dir =
   let open Memo.O in
@@ -216,12 +225,12 @@ let compile_module sctx ~obj_dir (m : Module.t) ~includes:(file_deps, iflags)
   let+ () =
     let* action_with_targets =
       let doc_dir = Path.build (Obj_dir.odoc_dir obj_dir) in
-      let* odoc = odoc sctx in
+      let* run_odoc = run_odoc sctx in
       let+ odoc_base_flags = odoc_base_flags sctx odoc_file in
       let open Action_builder.With_targets.O in
       Action_builder.with_no_targets file_deps
       >>> Action_builder.with_no_targets (module_deps m ~obj_dir ~dep_graphs)
-      >>> Command.run ~dir:doc_dir odoc
+      >>> run_odoc ~dir:doc_dir
             [ A "compile"
             ; odoc_base_flags
             ; A "-I"
@@ -241,11 +250,11 @@ let compile_mld sctx (m : Mld.t) ~includes ~doc_dir ~pkg =
   let open Memo.O in
   let odoc_file = Mld.odoc_file m ~doc_dir in
   let odoc_input = Mld.odoc_input m in
-  let* odoc = odoc sctx in
+  let* run_odoc = run_odoc sctx in
   let* odoc_base_flags = odoc_base_flags sctx odoc_input in
   let+ () =
     add_rule sctx
-      (Command.run ~dir:(Path.build doc_dir) odoc
+      (run_odoc ~dir:(Path.build doc_dir)
          [ A "compile"
          ; odoc_base_flags
          ; Command.Args.dyn includes
@@ -281,14 +290,13 @@ let link_odoc_rules sctx (odoc_file : odoc_artefact) ~pkg ~requires =
   let ctx = Super_context.context sctx in
   let deps = Dep.deps ctx pkg requires in
   let open Memo.O in
-  let* odoc = odoc sctx
+  let* run_odoc = run_odoc sctx
   and* odoc_base_flags = odoc_base_flags sctx odoc_file.odoc_file in
   add_rule sctx
     (let open Action_builder.With_targets.O in
     Action_builder.with_no_targets deps
-    >>> Command.run
+    >>> run_odoc
           ~dir:(Path.build (Paths.html_root ctx))
-          odoc
           [ A "link"
           ; odoc_base_flags
           ; odoc_include_flags ctx pkg requires
@@ -339,7 +347,7 @@ let setup_html sctx (odoc_file : odoc_artefact) =
       (odoc_file.html_dir, [ dummy ])
   in
   let open Memo.O in
-  let* odoc = odoc sctx in
+  let* run_odoc = run_odoc sctx in
   add_rule sctx
     (Action_builder.progn
        (Action_builder.with_no_targets
@@ -349,9 +357,8 @@ let setup_html sctx (odoc_file : odoc_artefact) =
                    [ Action.Remove_tree to_remove
                    ; Action.Mkdir (Path.build odoc_file.html_dir)
                    ])))
-       :: Command.run
+       :: run_odoc
             ~dir:(Path.build (Paths.html_root ctx))
-            odoc
             [ A "html-generate"
             ; A "-o"
             ; Path (Path.build (Paths.html_root ctx))
@@ -363,9 +370,9 @@ let setup_html sctx (odoc_file : odoc_artefact) =
 let setup_css_rule sctx =
   let open Memo.O in
   let ctx = Super_context.context sctx in
-  let* odoc = odoc sctx in
+  let* run_odoc = run_odoc sctx in
   add_rule sctx
-    (Command.run ~dir:(Path.build ctx.build_dir) odoc
+    (run_odoc ~dir:(Path.build ctx.build_dir)
        [ A "support-files"
        ; A "-o"
        ; Path (Path.build (Paths.html_root ctx))
diff --git a/test/blackbox-tests/test-cases/odoc/github1117.t b/test/blackbox-tests/test-cases/odoc/github1117.t
new file mode 100644
index 000000000000..b8fc119fe95d
--- /dev/null
+++ b/test/blackbox-tests/test-cases/odoc/github1117.t
@@ -0,0 +1,34 @@
+The rules that call odoc know that it is going to read the ODOC_SYNTAX
+variable, and can rebuild as needed.
+
+  $ cat > dune-project << EOF
+  > (lang dune 1.1)
+  > (package (name l))
+  > EOF
+
+  $ cat > dune << EOF
+  > (library
+  >  (public_name l))
+  > EOF
+
+  $ cat > l.ml << EOF
+  > module type X = sig end
+  > EOF
+
+  $ detect () {
+  > if grep -q '>sig<' $1 ; then
+  >   echo it is ocaml
+  > elif grep -q '{ ... }' $1 ; then
+  >   echo it is reason
+  > else
+  >   echo it is unknown
+  > fi
+  > }
+
+  $ dune build @doc
+  $ detect _build/default/_doc/_html/l/L/index.html 
+  it is ocaml
+
+  $ ODOC_SYNTAX=re dune build @doc
+  $ detect _build/default/_doc/_html/l/L/index.html 
+  it is reason