diff --git a/dune-project b/dune-project
index 5b306e15..3af5d10e 100644
--- a/dune-project
+++ b/dune-project
@@ -16,7 +16,7 @@
   astring
   (fmt (>= 0.8.9))
   logs
-  cmdliner
+  (cmdliner (> 1.0.4))
   (tar (>= 2.0))
   (tar-unix (>= 2.0))
   yojson
diff --git a/example.windows.spec b/example.windows.spec
new file mode 100644
index 00000000..d9e218dc
--- /dev/null
+++ b/example.windows.spec
@@ -0,0 +1,49 @@
+; This script builds OBuilder itself using a snapshot of the
+; ocaml/opam:window-mingw-20H2-ocaml-4.12 base image.
+;
+; Run it from the top-level of the OBuilder source tree, e.g.
+;
+;   dune exec -- obuilder build --docker-backend=../var -f example.windows.spec .
+;
+; The result can then be found in ../var/HASH/rootfs/ (where HASH is
+; displayed at the end of the build).
+
+((build dev
+	((from ocaml/opam@sha256:875f8962b438f16fd20076730d8db3f328155ab2ce9499b375bda5c4d9da9788)
+	 (workdir /project)
+	 (env OPAM_HASH "96d0b8dbb64a291108c8bccb5cdbb1936f853207") ; Fix the version of opam-repository we want
+	 (shell C:/cygwin64/bin/bash.exe --login -c)
+	 (run
+	  (network "Default Switch")
+	  (shell
+	   "cd /home/opam/opam-repository \
+	    && (git cat-file -e $OPAM_HASH || git fetch origin master) \
+	    && git reset -q --hard $OPAM_HASH \
+	    && git log --no-decorate -n1 --oneline \
+	    && opam update -u"))
+	 (shell C:/Windows/System32/cmd.exe /S /C)
+	 ; Copy just the opam file first (helps caching)
+	 (copy (src obuilder-spec.opam obuilder.opam) (dst ./))
+	 (run (shell "ocaml-env exec --64 -- opam pin add -yn ."))
+	 ; Install OS package dependencies
+	 (run
+	  (cache (opam-archives (target /opam/.opam/download-cache)))
+	  (shell "ocaml-env exec --64 -- opam depext -yu obuilder"))
+	 ; Install OCaml dependencies
+	 (run
+	  (cache (opam-archives (target /opam/.opam/download-cache)))
+	  (shell "ocaml-env exec --64 -- opam install --deps-only -t obuilder"))
+	 (copy                                                  ; Copy the rest of the source code
+	                                                          (src .)
+	                                                          (dst /project/)
+	                                                          (exclude .git _build _opam))
+	 (run (shell "ocaml-env exec --64 -- dune build @install @runtest"))))    ; Build and test
+ ; Now generate a small runtime image with just the resulting binary:
+ (from mcr.microsoft.com/windows/nanoserver:20H2)
+ (copy (from (build dev))
+       (src /cygwin64/usr/x86_64-w64-mingw32/sys-root/mingw/bin/libsqlite3-0.dll)
+       (dst /obuilder/))
+ (copy (from (build dev))
+       (src /project/_build/default/main.exe)
+       (dst /obuilder/obuilder.exe))
+ (run (shell "/obuilder/obuilder.exe --help")))
diff --git a/lib_spec/docker.ml b/lib_spec/docker.ml
index cf6ec1d9..cbf6dcc1 100644
--- a/lib_spec/docker.ml
+++ b/lib_spec/docker.ml
@@ -10,9 +10,15 @@ let default_ctx = {
 let pp_pair f (k, v) =
   Fmt.pf f "%s=%s" k v
 
-let pp_wrap =
+let pp_escape ~escape =
+  match escape with
+  | '\\' -> Fmt.any " \\@\n    "
+  | '`' -> Fmt.any " `@\n    "
+  | _ -> assert false
+
+let pp_wrap ~escape =
   Fmt.using (String.split_on_char '\n')
-    Fmt.(list ~sep:(unit " \\@\n    ") (using String.trim string))
+    Fmt.(list ~sep:(pp_escape ~escape) (using String.trim string))
 
 let pp_cache ~ctx f { Cache.id; target; buildkit_options } =
   let buildkit_options = match ctx.user with
@@ -40,11 +46,11 @@ let pp_mount_secret ~ctx f { Secret.id; target; buildkit_options } =
   in
   Fmt.pf f "%a" Fmt.(list ~sep:(unit ",") pp_pair) buildkit_options
 
-let pp_run ~ctx f { Spec.cache; shell; secrets; network = _ } =
+let pp_run ~escape ~ctx f { Spec.cache; shell; secrets; network = _ } =
   Fmt.pf f "RUN %a%a%a"
     Fmt.(list (pp_mount_secret ~ctx ++ const string " ")) secrets
     Fmt.(list (pp_cache ~ctx ++ const string " ")) cache
-    pp_wrap shell
+    (pp_wrap ~escape) shell
 
 let pp_copy ~ctx f { Spec.from; src; dst; exclude = _ } =
   let from = match from with
@@ -79,31 +85,35 @@ let quote ~escape v =
   Buffer.add_substring buf v !j (len - !j);
   Buffer.contents buf
 
-let pp_op ~buildkit ctx f : Spec.op -> ctx = function
+let pp_op ~buildkit ~escape ctx f : Spec.op -> ctx = function
   | `Comment x                -> Fmt.pf f "# %s" x; ctx
   | `Workdir x                -> Fmt.pf f "WORKDIR %s" x; ctx
   | `Shell xs                 -> Fmt.pf f "SHELL [ %a ]" Fmt.(list ~sep:comma (quote string)) xs; ctx
-  | `Run x when buildkit      -> pp_run ~ctx f x; ctx
-  | `Run x                    -> pp_run ~ctx f { x with cache = []; secrets = []}; ctx
+  | `Run x when buildkit      -> pp_run ~escape ~ctx f x; ctx
+  | `Run x                    -> pp_run ~escape ~ctx f { x with cache = []; secrets = []}; ctx
   | `Copy x                   -> pp_copy ~ctx f x; ctx
   | `User (`Unix { uid; gid } as u) -> Fmt.pf f "USER %d:%d" uid gid; { user = u }
   | `User (`Windows { name } as u) -> Fmt.pf f "USER %s" name; { user = u }
-  | `Env (k, v)               -> Fmt.pf f "ENV %s=\"%s\"" k (quote ~escape:'\\' v); ctx
+  | `Env (k, v)               -> Fmt.pf f "ENV %s=\"%s\"" k (quote ~escape v); ctx
 
-let rec convert ~buildkit f (name, { Spec.child_builds; from; ops }) =
+let rec convert ~buildkit ~escape f (name, { Spec.child_builds; from; ops }) =
   child_builds |> List.iter (fun (name, spec) ->
-      convert ~buildkit f (Some name, spec);
+      convert ~buildkit ~escape f (Some name, spec);
       Format.pp_print_newline f ();
     );
   Fmt.pf f "@[<h>FROM %s%a@]@." from Fmt.(option (const string " as " ++ string)) name;
   let (_ : ctx) = List.fold_left (fun ctx op ->
       Format.pp_open_hbox f ();
-      let ctx = pp_op ~buildkit ctx f op in
+      let ctx = pp_op ~buildkit ~escape ctx f op in
       Format.pp_close_box f ();
       Format.pp_print_newline f ();
       ctx
     ) default_ctx ops
   in ()
 
-let dockerfile_of_spec ~buildkit t =
-  Fmt.strf "%a" (convert ~buildkit) (None, t)
+let dockerfile_of_spec ~buildkit ~escape t =
+  Fmt.str "%a" (fun f ->
+      if escape <> '\\' then
+        (Fmt.pf f "@[<h>#escape=%c@]@." escape;
+         convert ~buildkit ~escape f)
+      else convert ~buildkit ~escape f) (None, t)
diff --git a/lib_spec/docker.mli b/lib_spec/docker.mli
index 83fe91e4..0e23fbb1 100644
--- a/lib_spec/docker.mli
+++ b/lib_spec/docker.mli
@@ -1,5 +1,6 @@
-val dockerfile_of_spec : buildkit:bool -> Spec.t -> string
-(** [dockerfile_of_spec x] produces a Dockerfile that aims to be equivalent to [x].
+val dockerfile_of_spec : buildkit:bool -> escape:char -> Spec.t -> string
+(** [dockerfile_of_spec ~buildkit ~escape x] produces a Dockerfile
+   that aims to be equivalent to [x].
 
     However, note that:
 
diff --git a/main.ml b/main.ml
index 16383138..f73e1d8d 100644
--- a/main.ml
+++ b/main.ml
@@ -83,10 +83,10 @@ let delete () store conf id =
     Builder.delete builder id ~log:(fun id -> Fmt.pr "Removing %s@." id)
   end
 
-let dockerfile () buildkit spec =
+let dockerfile () buildkit escape spec =
   Sexplib.Sexp.load_sexp spec
   |> Obuilder_spec.t_of_sexp
-  |> Obuilder_spec.Docker.dockerfile_of_spec ~buildkit
+  |> Obuilder_spec.Docker.dockerfile_of_spec ~buildkit ~escape
   |> print_endline
 
 open Cmdliner
@@ -178,9 +178,16 @@ let buildkit =
     ~doc:"Output extended BuildKit syntax"
     ["buildkit"]
 
+let escape =
+  Arg.value @@
+  Arg.opt Arg.char (if Sys.unix then '\\' else '`') @@
+  Arg.info
+    ~doc:"Dockerfile escape character. The default is '\\' on UNIX and '`' on Windows."
+    ["escape"]
+
 let dockerfile =
   let doc = "Convert a spec to Dockerfile format" in
-  Term.(const dockerfile $ setup_log $ buildkit $ spec_file),
+  Term.(const dockerfile $ setup_log $ buildkit $ escape $ spec_file),
   Term.info "dockerfile" ~doc
 
 let healthcheck =
diff --git a/obuilder.opam b/obuilder.opam
index 3b0a19ee..cdfbff1f 100644
--- a/obuilder.opam
+++ b/obuilder.opam
@@ -14,7 +14,7 @@ depends: [
   "astring"
   "fmt" {>= "0.8.9"}
   "logs"
-  "cmdliner"
+  "cmdliner" {> "1.0.4"}
   "tar" {>= "2.0"}
   "tar-unix" {>= "2.0"}
   "yojson"
@@ -45,6 +45,7 @@ build: [
 ]
 dev-repo: "git+https://github.com/ocurrent/obuilder.git"
 pin-depends: [
+  ["cmdliner.1.0.5" "git+https://github.com/dbuenzli/cmdliner.git#db4d02a9eb47b5c43127a67cb121004b03ea3719"]
   ["lwt.5.4.3" "git+https://github.com/MisterDA/lwt.git#e703de884a798b0c8c45c6f792691cdaf578d35b"]
   ["sha.1.15" "git+https://github.com/djs55/ocaml-sha.git#8b77ab306fc3a5e94219580d6a2c92bc11745d60"]
   ["tar.2.0.0" "git+https://github.com/MisterDA/ocaml-tar.git#47d20548d39337009b6d73309eb2aab346494e76"]
diff --git a/obuilder.opam.template b/obuilder.opam.template
index 0a1d7787..b7343c92 100644
--- a/obuilder.opam.template
+++ b/obuilder.opam.template
@@ -1,4 +1,5 @@
 pin-depends: [
+  ["cmdliner.1.0.5" "git+https://github.com/dbuenzli/cmdliner.git#db4d02a9eb47b5c43127a67cb121004b03ea3719"]
   ["lwt.5.4.3" "git+https://github.com/MisterDA/lwt.git#e703de884a798b0c8c45c6f792691cdaf578d35b"]
   ["sha.1.15" "git+https://github.com/djs55/ocaml-sha.git#8b77ab306fc3a5e94219580d6a2c92bc11745d60"]
   ["tar.2.0.0" "git+https://github.com/MisterDA/ocaml-tar.git#47d20548d39337009b6d73309eb2aab346494e76"]
diff --git a/test/test.ml b/test/test.ml
index f369ac06..e79d0f9f 100644
--- a/test/test.ml
+++ b/test/test.ml
@@ -460,10 +460,10 @@ let test_sexp () =
       (user (uid 1) (gid 2))
      )|}
 
-let test_docker () =
+let test_docker_unix () =
   let test ~buildkit name expect sexp =
     let spec = Spec.t_of_sexp (Sexplib.Sexp.of_string sexp) in
-    let got = Obuilder_spec.Docker.dockerfile_of_spec ~buildkit spec in
+    let got = Obuilder_spec.Docker.dockerfile_of_spec ~buildkit ~escape:'\\' spec in
     let expect = remove_indent expect in
     Alcotest.(check string) name expect got
   in
@@ -555,6 +555,105 @@ let test_docker () =
        (shell "command1"))
      ) |}
 
+let test_docker_windows () =
+  let test ~buildkit name expect sexp =
+    let spec = Spec.t_of_sexp (Sexplib.Sexp.of_string sexp) in
+    let got = Obuilder_spec.Docker.dockerfile_of_spec ~buildkit ~escape:'`' spec in
+    let expect = remove_indent expect in
+    Alcotest.(check string) name expect got
+  in
+  test ~buildkit:false "Dockerfile"
+    {| #escape=`
+       FROM base
+       # A test comment
+       WORKDIR C:/src
+       RUN command1
+       SHELL [ "C:/Windows/System32/cmd.exe", "/c" ]
+       RUN command2 && `
+           command3
+       COPY a b c
+       COPY a b c
+       ENV DEBUG="1"
+       USER Zaphod
+       COPY a b c
+    |} {|
+     ((from base)
+      (comment "A test comment")
+      (workdir C:/src)
+      (run (shell "command1"))
+      (shell C:/Windows/System32/cmd.exe /c)
+      (run
+       (cache (a (target /data))
+              (b (target /srv)))
+       (shell "command2 &&
+               command3"))
+      (copy (src a b) (dst c))
+      (copy (src a b) (dst c) (exclude .git _build))
+      (env DEBUG 1)
+      (user (name Zaphod))
+      (copy (src a b) (dst c))
+     ) |};
+  test ~buildkit:true "BuildKit"
+    {| #escape=`
+       FROM base
+       # A test comment
+       WORKDIR /src
+       RUN command1
+       SHELL [ "C:/Windows/System32/cmd.exe", "/c" ]
+       RUN --mount=type=cache,id=a,target=/data,uid=0 --mount=type=cache,id=b,target=/srv,uid=0 command2
+       COPY a b c
+       COPY a b c
+       ENV DEBUG="1"
+       USER Zaphod
+       COPY a b c
+    |} {|
+     ((from base)
+      (comment "A test comment")
+      (workdir /src)
+      (run (shell "command1"))
+      (shell C:/Windows/System32/cmd.exe /c)
+      (run
+       (cache (a (target /data))
+              (b (target /srv)))
+       (shell "command2"))
+      (copy (src a b) (dst c))
+      (copy (src a b) (dst c) (exclude .git _build))
+      (env DEBUG 1)
+      (user (name Zaphod))
+      (copy (src a b) (dst c))
+     ) |};
+  test ~buildkit:false "Multi-stage"
+    {| #escape=`
+       FROM base as tools
+       RUN make tools
+
+       FROM base
+       COPY --from=tools binary /usr/local/bin/
+    |} {|
+     ((build tools
+             ((from base)
+              (run (shell "make tools"))))
+      (from base)
+      (copy (from (build tools)) (src binary) (dst /usr/local/bin/))
+     ) |};
+  test ~buildkit:true "Secrets"
+    {| #escape=`
+       FROM base as tools
+       RUN make tools
+
+       FROM base
+       RUN --mount=type=secret,id=a,target=/secrets/a,uid=0 --mount=type=secret,id=b,target=/secrets/b,uid=0 command1
+    |} {|
+     ((build tools
+            ((from base)
+             (run (shell "make tools"))))
+      (from base)
+      (run
+       (secrets (a (target /secrets/a))
+                (b (target /secrets/b)))
+       (shell "command1"))
+     ) |}
+
 let manifest =
   Alcotest.result
     (Alcotest.testable
@@ -696,7 +795,8 @@ let main_unix () =
       "spec", [
         test_case_sync "Sexp"     `Quick test_sexp;
         test_case_sync "Cache ID" `Quick test_cache_id;
-        test_case_sync "Docker"   `Quick test_docker;
+        test_case_sync "Docker UNIX"    `Quick test_docker_unix;
+        test_case_sync "Docker Windows" `Quick test_docker_windows;
       ];
       "build", [
         test_case "Simple"     `Quick test_simple;