diff --git a/luametalatex-back-pdf.lua b/luametalatex-back-pdf.lua
index aa72599..cd3f6e0 100644
--- a/luametalatex-back-pdf.lua
+++ b/luametalatex-back-pdf.lua
@@ -51,10 +51,15 @@ local colorstacks = {{
     page_stack = {"0 g 0 G"},
   }}
 local spacer_cmd = token.command_id'spacer'
+local output_directory = arg['output-directory']
+local dir_sep = '/' -- FIXME
 local function get_pfile()
   if not pfile then
     pdfname = tex.jobname .. '.pdf'
-    pfile = newpdf.open(tex.jobname .. '.pdf')
+    if output_directory then
+      pdfname = output_directory .. dir_sep .. pdfname
+    end
+    pfile = newpdf.open(pdfname)
   end
   return pfile
 end
diff --git a/luametalatex-basecallbacks.lua b/luametalatex-basecallbacks.lua
index d298131..dea0ce8 100644
--- a/luametalatex-basecallbacks.lua
+++ b/luametalatex-basecallbacks.lua
@@ -4,6 +4,27 @@ local read_tfm = font.read_tfm
 local font_define = font.define
 local callbacks = require'luametalatex-callbacks'
 
+local find_file = kpse.find_file
+local output_directory = arg['output-directory']
+
+local dir_sep = '/' -- FIXME
+
+if output_directory then
+  local old_find_file = find_file
+  local kpse_absolute = kpse.is_absolute
+  local attributes = lfs.attributes
+  function find_file(path, kind, must_exists)
+    --kind is always "tex"
+    if not kpse_absolute(path) then
+      local new_path = output_directory .. dir_sep .. path
+      if attributes(new_path, 'mode') == 'file' then
+        return new_path
+      end
+    end
+    return old_find_file(path, kind, must_exists)
+  end
+end
+
 if status.ini_version then
   function callbacks.define_font(name, size)
     local f = read_tfm(name, size)
@@ -26,7 +47,11 @@ else
 end
 callbacks.__freeze'define_font'
 
-function callbacks.find_log_file(name) return name end
+if output_directory then
+  function callbacks.find_log_file(name) return output_directory .. dir_sep .. name end
+else
+  function callbacks.find_log_file(name) return name end
+end
 callbacks.__freeze'find_log_file'
 
 -- find_data_file is not an engine callback in luametatex, so we don't __freeze it
@@ -38,11 +63,11 @@ if status.ini_version then
     if name == 'expl3.ltx' then
       name = 'luametalatex-ltexpl-hook'
     end
-    return kpse.find_file(name, 'tex', true)
+    return find_file(name, 'tex', true)
   end
 end
   local function normal_find_data_file(name)
-    return kpse.find_file(name, 'tex', true)
+    return find_file(name, 'tex', true)
   end
 function callbacks.open_data_file(name)
   local find_callback = callbacks.find_data_file
@@ -50,7 +75,7 @@ function callbacks.open_data_file(name)
   if find_callback then
     path = find_callback(name)
   else
-    path = kpse.find_file(name, 'tex', true)
+    path = find_file(name, 'tex', true)
   end
   if not path then return end
 
diff --git a/luametalatex-firstcode.lua b/luametalatex-firstcode.lua
index 39a07ba..77186de 100644
--- a/luametalatex-firstcode.lua
+++ b/luametalatex-firstcode.lua
@@ -55,7 +55,6 @@ do
   end
 end
 
-
 local new_whatsit = require'luametalatex-whatsits'.new
 local whatsit_id = node.id'whatsit'
 local spacer_cmd, relax_cmd = token.command_id'spacer', token.command_id'relax'
@@ -98,12 +97,18 @@ local immediate_flag = lmlt.flag.immediate
 local l = lpeg or require'lpeg'
 local add_file_extension = l.Cs((1-('.' * (1-l.S'./\\')^0) * -1)^0 * (l.P(1)^1+l.Cc'.tex'))
 local ofiles, ifiles = {}, {}
+local output_directory = arg['output-directory']
+local dir_sep = '/' -- FIXME
 local function do_openout(p)
   if ofiles[p.file] then
     ofiles[p.file]:close()
   end
   local msg
-  ofiles[p.file], msg = io.open(add_file_extension:match(p.name), 'w')
+  local name = add_file_extension:match(p.name)
+  if output_directory then
+    name = output_directory .. dir_sep .. name
+  end
+  ofiles[p.file], msg = io.open(name, 'w')
   if not ofiles[p.file] then
     error(msg)
   end
diff --git a/luametalatex-lateinit.lua b/luametalatex-lateinit.lua
index 2d494a1..cab017e 100644
--- a/luametalatex-lateinit.lua
+++ b/luametalatex-lateinit.lua
@@ -104,6 +104,7 @@ end
 
 if initex then
   local build_bytecode = nil -- To be filled
+  local output_directory = arg['output-directory']
   function callbacks.pre_dump()
     local user_callback = callbacks.pre_dump
     if user_callback then user_callback() end
@@ -144,6 +145,9 @@ if initex then
       end
     end
     lua.bytecode[tex.count[262]+1] = build_bytecode(table.concat(prepared, '\n'))
+    if output_directory then
+      lfs.chdir(output_directory) -- We can't change the location TeX writes it's format to, so we change the current directory instead
+    end
   end
   callbacks.__freeze('pre_dump', true)
   return function(f)
diff --git a/luametalatex.so b/luametalatex.so
index 79cf863..ec1a711 100755
Binary files a/luametalatex.so and b/luametalatex.so differ