diff --git a/lib/reynard/external.rb b/lib/reynard/external.rb
index 54266a5..b3bd6ec 100644
--- a/lib/reynard/external.rb
+++ b/lib/reynard/external.rb
@@ -8,6 +8,7 @@ class External
     def initialize(path:, ref:)
       @path = path
       @relative_path, @anchor = ref.split('#', 2)
+      @filename = File.expand_path(@relative_path, @path)
     end
 
     def path
@@ -22,11 +23,14 @@ def data
       end
     end
 
+    def filesystem_path
+      File.dirname(@filename)
+    end
+
     private
 
     def filename
-      filename = File.expand_path(@relative_path, @path)
-      return filename if filename.start_with?(@path)
+      return @filename if @filename.start_with?(@path)
 
       raise 'You are only allowed to reference files relative to the specification file.'
     end
diff --git a/lib/reynard/specification.rb b/lib/reynard/specification.rb
index 868e0da..28be257 100644
--- a/lib/reynard/specification.rb
+++ b/lib/reynard/specification.rb
@@ -14,7 +14,7 @@ def initialize(filename:)
 
     # Digs a value out of the specification, taking $ref into account.
     def dig(*path)
-      dig_into(@data, @data, path.dup)
+      dig_into(@data, @data, path.dup, File.dirname(@filename))
     end
 
     def servers
@@ -103,7 +103,7 @@ def read
     # rubocop:disable Metrics/AbcSize
     # rubocop:disable Metrics/CyclomaticComplexity
     # rubocop:disable Metrics/MethodLength
-    def dig_into(data, cursor, path)
+    def dig_into(data, cursor, path, filesystem_path)
       while path.length.positive?
         cursor = cursor[path.first]
         return unless cursor
@@ -118,7 +118,8 @@ def dig_into(data, cursor, path)
           cursor = data
         # References another file, with an optional anchor to an element in the data.
         when %r{\A\./}
-          external = External.new(path: File.dirname(@filename), ref: cursor['$ref'])
+          external = External.new(path: filesystem_path, ref: cursor['$ref'])
+          filesystem_path = external.filesystem_path
           path = external.path + path
           cursor = external.data
         end
diff --git a/test/files/openapi/schemas/author.yml b/test/files/openapi/schemas/author.yml
index cd68827..88211d3 100644
--- a/test/files/openapi/schemas/author.yml
+++ b/test/files/openapi/schemas/author.yml
@@ -8,4 +8,6 @@ properties:
     type: integer
   name:
     type: string
+  bio:
+    "$ref": "./bio.yml"
 additionalProperties: false
diff --git a/test/files/openapi/schemas/bio.yml b/test/files/openapi/schemas/bio.yml
new file mode 100644
index 0000000..a86d040
--- /dev/null
+++ b/test/files/openapi/schemas/bio.yml
@@ -0,0 +1,9 @@
+type: object
+title: Bio
+description: >-
+  Biographical details about an author.
+required: [age]
+properties:
+  age:
+    type: integer
+additionalProperties: false
diff --git a/test/reynard/object_builder_test.rb b/test/reynard/object_builder_test.rb
index 910e329..1cd1f4c 100644
--- a/test/reynard/object_builder_test.rb
+++ b/test/reynard/object_builder_test.rb
@@ -61,11 +61,14 @@ def setup
       author = Reynard::ObjectBuilder.new(
         schema: schema,
         inflector: @inflector,
-        parsed_body: { id: 42, name: 'Jerry Writer' }
+        parsed_body: {
+          id: 42, name: 'Jerry Writer', bio: { age: 42 }
+        }
       ).call
       assert_model_name('Author', author)
       assert_equal 42, author.id
       assert_equal 'Jerry Writer', author.name
+      assert_equal 42, author.bio.age
     end
   end
 
diff --git a/test/reynard/specification_test.rb b/test/reynard/specification_test.rb
index 5db3dcf..6822071 100644
--- a/test/reynard/specification_test.rb
+++ b/test/reynard/specification_test.rb
@@ -234,6 +234,15 @@ def setup
       assert_equal 'integer', data
     end
 
+    test 'digs into an external file through a reference in an external file' do
+      data = @specification.dig(
+        'paths', '/authors/{id}', 'get', 'responses', '200',
+        'content', 'application/json', 'schema',
+        'properties', 'bio', 'properties', 'age', 'type'
+      )
+      assert_equal 'integer', data
+    end
+
     test 'digs into an external file with an anchor' do
       data = @specification.dig(
         'paths', '/authors/{id}', 'get', 'responses', 'default',
@@ -242,7 +251,7 @@ def setup
       assert_equal %w[code message], data['required']
     end
 
-    test 'digs into an external file through a refenence with with an anchor' do
+    test 'digs into an external file through a reference with with an anchor' do
       data = @specification.dig(
         'paths', '/authors/{id}', 'get', 'responses', 'default',
         'content', 'application/json', 'schema', 'required'