diff --git a/src/openapi_schema.erl b/src/openapi_schema.erl
index e923d91..de32c38 100644
--- a/src/openapi_schema.erl
+++ b/src/openapi_schema.erl
@@ -47,7 +47,7 @@ process(Input, #{} = Opts) ->
     (patch,Flag) when Flag == true; Flag == false -> ok;
     (extra_obj_key,Flag) when Flag == drop; Flag == error -> ok;
     (required_obj_keys,Flag) when Flag == drop; Flag == error -> ok;
-    (access_type,Flag) when Flag == read; Flag == write -> ok;
+    (access_type,Flag) when Flag == read; Flag == write; Flag == raw -> ok;
     (explain,FlagList) -> check_explain_keys(FlagList);
     (K,V) -> error({unknown_option,K,V})
   end, Opts),
@@ -285,9 +285,11 @@ encode3(#{type := <<"object">>, properties := Properties} = Schema, #{query := Q
 
       RequiredKeys = get_required_keys(Schema, Opts),
       IsReadOnly = maps:get(readOnly, Prop, false),
+      IsWriteOnly = maps:get(writeOnly, Prop, false),
       IsPrimary = maps:get('x-primary-key', Prop, false),
       IsRequired = (lists:member(FieldBin, RequiredKeys) orelse IsPrimary),
-      IsWriteAccess = maps:get(access_type, Opts, read) == write,
+      IsReadAccess = maps:get(access_type, Opts, raw) == read,
+      IsWriteAccess = maps:get(access_type, Opts, raw) == write,
 
       ApplyDefaults = maps:get(apply_defaults, Opts, false),
       EffectiveValue = case {Input, Prop} of
@@ -318,9 +320,12 @@ encode3(#{type := <<"object">>, properties := Properties} = Schema, #{query := Q
         {ok, Null} when (Null == null orelse Null == undefined) andalso
           not NullableProp andalso not Patching ->
           Obj;
-        % Silently drop read only fields with write access
+        % Silently drop readOnly fields on write
         {ok, _Value} when IsWriteAccess andalso IsReadOnly andalso (not IsRequired) ->
           Obj;
+        % Silently drop writeOnly fields on read
+        {ok, _Value} when IsReadAccess andalso IsWriteOnly andalso (not IsRequired) ->
+          Obj;
         {ok, Value} ->
           case encode3(Prop#{nullable => NullableProp}, Opts, Value, Path ++ [Field]) of
             {error, _} = E ->
diff --git a/test/example-openapi.json b/test/example-openapi.json
new file mode 100644
index 0000000..6e997ad
--- /dev/null
+++ b/test/example-openapi.json
@@ -0,0 +1,41 @@
+{
+  "openapi": "3.1.1",
+  "info": {
+    "contact": { "email": "hello@exampl.com", "name": "Test", "url": "https://example.com/" },
+    "description": "dummy desc",
+    "title": "Test API",
+    "version": "0.1.0"
+  },
+  "components": {
+    "schemas": {
+      "external_validators_simple": {
+        "type": "string",
+        "format": "no_space"
+      },
+      "external_validators_array": {
+        "type": "array",
+        "items": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "format": "no_space"
+          }
+        }
+      },
+      "external_validators_object": {
+        "type": "object",
+        "properties": {
+          "in_object": {
+            "type": "object",
+            "properties": {
+              "prop1": {
+                "type": "string",
+                "format": "no_space"
+              }
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/test/openapi_handler_SUITE.erl b/test/openapi_handler_SUITE.erl
index b6b227b..027dabb 100644
--- a/test/openapi_handler_SUITE.erl
+++ b/test/openapi_handler_SUITE.erl
@@ -438,18 +438,12 @@ required_keys_filter(_) ->
 
 
 select_not_filters_required_keys(_) ->
+  % p3 is 'writeOnly', so it should be dropped in results
   #{elements := [Elem1,Elem1]} = openapi_client:call(test_schema_api, selectCollectionFields,
       #{json_body => #{p1 => 1, p2 => 2, p3 => 3, p4 => 4, p5 => 5}}),
-  #{p1 := 1, p2 := 2, p3 := 3, p4 := 4, p5 :=5} = Elem1,
+  #{p1 := 1, p2 := 2, p4 := 4, p5 :=5} = Elem1,
 
-  % p1, p2 are 'readOnly' required keys
-  #{elements := [Elem2,Elem2]} = openapi_client:call(test_schema_api, selectCollectionFields,
-      #{json_body => #{p1 => 1, p2 => 2, p3 => 3, p4 => 4, p5 => 5}, select => <<"p3">>}),
-  #{p1 := 1, p2 := 2, p3 := 3} = Elem2,
-  undefined = maps:get(p4, Elem2, undefined),
-  undefined = maps:get(p5, Elem2, undefined),
-
-  % p3 is 'writeOnly' required key
+  % p1, p2 are required keys, so they are returned despite not explicitly requested
   #{elements := [Elem3,Elem3]} = openapi_client:call(test_schema_api, selectCollectionFields,
       #{json_body => #{p1 => 1, p2 => 2, p3 => 3, p4 => 4, p5 => 5}, select => <<"p4">>}),
   #{p1 := 1, p2 := 2, p4 := 4} = Elem3,
diff --git a/test/openapi_schema_SUITE.erl b/test/openapi_schema_SUITE.erl
index c3d642c..9f5df55 100644
--- a/test/openapi_schema_SUITE.erl
+++ b/test/openapi_schema_SUITE.erl
@@ -35,6 +35,7 @@ groups() ->
       check_explain_on_error,
       one_of_integer_const,
       one_of_const_default,
+      drop_unidirectional_keys,
       filter_read_only_props
     ]},
     {introspection, [], [
@@ -432,6 +433,27 @@ one_of_const_default(_) ->
         #{schema => FooType, apply_defaults => true}),
   ok.
 
+
+drop_unidirectional_keys(_) ->
+  Schema = #{
+    type => <<"object">>,
+    properties => #{
+      pn => #{type => <<"integer">>},
+      pr => #{type => <<"integer">>, readOnly => true},
+      pw => #{type => <<"integer">>, writeOnly => true}
+    }
+  },
+  % 'raw' access does not involve any read/write filtering logic
+  ObjRaw = openapi_schema:process(#{pn => 1, pr => 2, pw => 3}, #{schema => Schema, extra_obj_key => drop, access_type => raw}),
+  [pn, pr, pw] = lists:sort(maps:keys(ObjRaw)),
+  % 'write' access drops readOnly properties
+  ObjW = openapi_schema:process(#{pn => 1, pr => 2, pw => 3}, #{schema => Schema, extra_obj_key => drop, access_type => write}),
+  [pn, pw] = lists:sort(maps:keys(ObjW)),
+  % 'read' access drops writeOnly properties
+  ObjR = openapi_schema:process(#{pn => 1, pr => 2, pw => 3}, #{schema => Schema, extra_obj_key => drop, access_type => read}),
+  [pn, pr] = lists:sort(maps:keys(ObjR)),
+  ok.
+
 filter_read_only_props(_) ->
   Schema = persistent_term:get({openapi_handler_schema,test_openapi}),
   Json = #{