diff --git a/example/README.md b/example/README.md
index 7e4d20092..9608622fd 100644
--- a/example/README.md
+++ b/example/README.md
@@ -53,11 +53,11 @@ COMMANDS
        validate [--debug] [OPTION]… [ARG]…
            Validate a module
 
-       wasm2wat [--emit-file] [OPTION]… [ARG]…
+       wasm2wat [--emit-file] [--output=FILE] [OPTION]… ARG
            Generate a text format file (.wat) from a binary format file
            (.wasm)
 
-       wat2wasm [OPTION]… [ARG]…
+       wat2wasm [OPTION]… ARG
            Generate a binary format file (.wasm) from a text format file
            (.wat)
 
diff --git a/example/wasm2wat/README.md b/example/wasm2wat/README.md
index 655f7ebc0..352f60c9a 100644
--- a/example/wasm2wat/README.md
+++ b/example/wasm2wat/README.md
@@ -28,12 +28,15 @@ NAME
        file (.wasm)
 
 SYNOPSIS
-       owi wasm2wat [--emit-file] [OPTION]… [ARG]…
+       owi wasm2wat [--emit-file] [--output=FILE] [OPTION]… ARG
 
 OPTIONS
        --emit-file
            emit (.wat) files from corresponding (.wasm) files
 
+       -o FILE, --output=FILE
+           wasm
+
 COMMON OPTIONS
        --help[=FMT] (default=auto)
            Show this help in format FMT. The value FMT must be one of auto,
diff --git a/example/wat2wasm/README.md b/example/wat2wasm/README.md
index caf044b72..3877b02fb 100644
--- a/example/wat2wasm/README.md
+++ b/example/wat2wasm/README.md
@@ -34,12 +34,15 @@ NAME
        format file (.wat)
 
 SYNOPSIS
-       owi wat2wasm [OPTION]… [ARG]…
+       owi wat2wasm [OPTION]… ARG
 
 OPTIONS
        -d, --debug
            debug mode
 
+       -o FILE, --output=FILE
+           wat
+
        --optimize
            optimize mode
 
diff --git a/src/ast/binary_encoder.ml b/src/ast/binary_encoder.ml
index e15f83ec7..ac5136d16 100644
--- a/src/ast/binary_encoder.ml
+++ b/src/ast/binary_encoder.ml
@@ -759,18 +759,17 @@ let encode
   encode_section buf '\x0B' encode_datas data;
   Buffer.contents buf
 
-let write_file filename content =
+let write_file outfile filename content =
   let _dir, filename = Fpath.split_base filename in
-  let filename, _ext = Fpath.split_ext filename in
-  let filename = Fpath.add_ext ".wasm" filename in
-  let fullpath = Fpath.add_seg _dir (Fpath.to_string filename) in
-  let filename = Fpath.to_string fullpath in
+  let filename = Fpath.set_ext "wasm" filename in
+  let filename = match outfile with Some name -> Fpath.v name | None -> filename in
+  let filename = Fpath.to_string filename in
   let oc = Out_channel.open_bin filename in
   Out_channel.output_string oc content;
   Out_channel.close oc
 
-let convert (filename : Fpath.t) ~unsafe ~optimize m =
+let convert (outfile: string option) (filename : Fpath.t) ~unsafe ~optimize m =
   Log.debug0 "bin encoding ...@\n";
   let+ m = Compile.Text.until_optimize ~unsafe ~optimize m in
   let content = encode m in
-  write_file filename content
+  write_file outfile filename content
diff --git a/src/ast/binary_encoder.mli b/src/ast/binary_encoder.mli
index d1481b2c5..2c020b45a 100644
--- a/src/ast/binary_encoder.mli
+++ b/src/ast/binary_encoder.mli
@@ -3,7 +3,8 @@
 (* Written by the Owi programmers *)
 
 val convert :
-     Fpath.t
+     string option
+  -> Fpath.t
   -> unsafe:bool
   -> optimize:bool
   -> Text.modul
diff --git a/src/bin/owi.ml b/src/bin/owi.ml
index 56cd947d1..7d501f794 100644
--- a/src/bin/owi.ml
+++ b/src/bin/owi.ml
@@ -39,6 +39,16 @@ let files =
   let f = existing_non_dir_file in
   Cmdliner.Arg.(value & pos_all f [] (info [] ~doc))
 
+let sourcefile ty =
+  let doc = Fmt.str "%s source file" ty in
+  let f = existing_non_dir_file in
+  Cmdliner.Arg.(required & pos 0 (some f) None (info [] ~doc))
+
+let outfile ty =
+  let doc = Fmt.str "%s" ty in
+  Cmdliner.Arg.(
+    value & opt (some string) None & info [ "o"; "output" ] ~docv:"FILE" ~doc )
+
 let emit_files =
   let doc = "emit (.wat) files from corresponding (.wasm) files" in
   Cmdliner.Arg.(value & flag & info [ "emit-file" ] ~doc)
@@ -249,7 +259,8 @@ let wasm2wat_cmd =
     let man = [] @ shared_man in
     Cmd.info "wasm2wat" ~version ~doc ~sdocs ~man
   in
-  Cmd.v info Term.(const Cmd_wasm2wat.cmd $ files $ emit_files)
+  Cmd.v info
+    Term.(const Cmd_wasm2wat.cmd $ sourcefile "wasm" $ emit_files $ outfile "wasm")
 
 let wat2wasm_cmd =
   let open Cmdliner in
@@ -261,7 +272,9 @@ let wat2wasm_cmd =
     Cmd.info "wat2wasm" ~version ~doc ~sdocs ~man
   in
   Cmd.v info
-    Term.(const Cmd_wat2wasm.cmd $ profiling $ debug $ unsafe $ optimize $ files)
+    Term.(
+      const Cmd_wat2wasm.cmd $ profiling $ debug $ unsafe $ optimize
+      $ outfile "wat" $ sourcefile "wat" )
 
 let cli =
   let open Cmdliner in
diff --git a/src/cmd/cmd_wasm2wat.ml b/src/cmd/cmd_wasm2wat.ml
index 046eb422b..4d0316357 100644
--- a/src/cmd/cmd_wasm2wat.ml
+++ b/src/cmd/cmd_wasm2wat.ml
@@ -5,16 +5,24 @@
 open Syntax
 
 (** Utility function to handle writing to a file or printing to stdout *)
-let cmd_one emitfile file =
+let cmd_one emitfile outfile file =
   let ext = Fpath.get_ext file in
-  let wat_file = Fpath.set_ext "wat" file in
+  let _dir, wat_file = Fpath.split_base file in
+  let wat_file = Fpath.set_ext "wat" wat_file in
 
   match ext with
   | ".wasm" ->
     let* m = Parse.Binary.Module.from_file file in
     let m = Binary_to_text.modul m in
-    if emitfile then Bos.OS.File.writef wat_file "%a@\n" Text.pp_modul m
+    let outname, output =
+      begin
+        match outfile with
+        | Some name -> Fpath.v name, true
+        | None -> wat_file, false
+      end
+    in
+    if emitfile || output then Bos.OS.File.writef outname "%a@\n" Text.pp_modul m
     else Ok (Fmt.pr "%a@\n" Text.pp_modul m)
   | ext -> Error (`Unsupported_file_extension ext)
 
-let cmd files emitfile = list_iter (cmd_one emitfile) files
+let cmd file emitfile outfile = cmd_one emitfile outfile file
diff --git a/src/cmd/cmd_wasm2wat.mli b/src/cmd/cmd_wasm2wat.mli
index 08e7444ae..2c7245d19 100644
--- a/src/cmd/cmd_wasm2wat.mli
+++ b/src/cmd/cmd_wasm2wat.mli
@@ -2,4 +2,4 @@
 (* Copyright © 2021-2024 OCamlPro *)
 (* Written by the Owi programmers *)
 
-val cmd : Fpath.t list -> bool -> unit Result.t
+val cmd : Fpath.t -> bool -> string option -> unit Result.t
diff --git a/src/cmd/cmd_wat2wasm.ml b/src/cmd/cmd_wat2wasm.ml
index 4192eaeb4..e820eadb2 100644
--- a/src/cmd/cmd_wat2wasm.ml
+++ b/src/cmd/cmd_wat2wasm.ml
@@ -4,15 +4,15 @@
 
 open Syntax
 
-let cmd_one ~unsafe ~optimize file =
+let cmd_one ~unsafe ~optimize outfile file =
   let ext = Fpath.get_ext file in
   match ext with
   | ".wat" ->
     let* modul = Parse.Text.Module.from_file file in
-    Binary_encoder.convert file ~unsafe ~optimize modul
+    Binary_encoder.convert outfile file ~unsafe ~optimize modul
   | ext -> Error (`Unsupported_file_extension ext)
 
-let cmd profiling debug unsafe optimize files =
+let cmd profiling debug unsafe optimize outfile file =
   if profiling then Log.profiling_on := true;
   if debug then Log.debug_on := true;
-  list_iter (cmd_one ~unsafe ~optimize) files
+  cmd_one ~unsafe ~optimize outfile file
diff --git a/src/cmd/cmd_wat2wasm.mli b/src/cmd/cmd_wat2wasm.mli
index 5cef2e0c3..585196f7c 100644
--- a/src/cmd/cmd_wat2wasm.mli
+++ b/src/cmd/cmd_wat2wasm.mli
@@ -2,4 +2,4 @@
 (* Copyright © 2021-2024 OCamlPro *)
 (* Written by the Owi programmers *)
 
-val cmd : bool -> bool -> bool -> bool -> Fpath.t list -> unit Result.t
+val cmd : bool -> bool -> bool -> bool -> string option -> Fpath.t -> unit Result.t
diff --git a/test/help/help.t b/test/help/help.t
index 2f5505199..2ff577330 100644
--- a/test/help/help.t
+++ b/test/help/help.t
@@ -31,11 +31,11 @@ no subcommand should print help
          validate [--debug] [OPTION]… [ARG]…
              Validate a module
   
-         wasm2wat [--emit-file] [OPTION]… [ARG]…
+         wasm2wat [--emit-file] [--output=FILE] [OPTION]… ARG
              Generate a text format file (.wat) from a binary format file
              (.wasm)
   
-         wat2wasm [OPTION]… [ARG]…
+         wat2wasm [OPTION]… ARG
              Generate a binary format file (.wasm) from a text format file
              (.wat)
   
diff --git a/test/wasm2wat/not_exists.t b/test/wasm2wat/not_exists.t
index ca3bc617b..6cc6a083e 100644
--- a/test/wasm2wat/not_exists.t
+++ b/test/wasm2wat/not_exists.t
@@ -1,6 +1,6 @@
   $ owi wasm2wat idontexist.wat
   owi: no file 'idontexist.wat'
-  Usage: owi wasm2wat [--emit-file] [OPTION]… [ARG]…
+  Usage: owi wasm2wat [--emit-file] [--output=FILE] [OPTION]… ARG
   Try 'owi wasm2wat --help' or 'owi --help' for more information.
   [124]
   $ owi wasm2wat bad.ext
diff --git a/test/wat2wasm/not_exists.t b/test/wat2wasm/not_exists.t
index b09f42d15..400c2f5ef 100644
--- a/test/wat2wasm/not_exists.t
+++ b/test/wat2wasm/not_exists.t
@@ -1,6 +1,6 @@
   $ owi wat2wasm not_exists.wat
   owi: no file 'not_exists.wat'
-  Usage: owi wat2wasm [OPTION]… [ARG]…
+  Usage: owi wat2wasm [OPTION]… ARG
   Try 'owi wat2wasm --help' or 'owi --help' for more information.
   [124]
   $ owi wat2wasm bad.ext