diff --git a/docs/channels.md b/docs/channels.md
index bafd8e6..9c9eddd 100644
--- a/docs/channels.md
+++ b/docs/channels.md
@@ -193,6 +193,6 @@ require 'rocketchat'
 
 rocket_server = RocketChat::Server.new('http://your.server.address/')
 session = rocket_server.login('username', 'password')
-session.channels.upload_file(room_id: 'GENERAL', file: File, msg: "Optional Message", description: "Optional Description", tmid: "Optional thread message id")
+session.channels.upload_file(room_id: 'GENERAL', file: File, filename: "Optional. The name of the file to use.", content_type: "Optional. The content type of the uploaded file", msg: "Optional Message", description: "Optional Description", tmid: "Optional thread message id")
 
 ```
diff --git a/docs/groups.md b/docs/groups.md
index 85684c0..7da14c9 100644
--- a/docs/groups.md
+++ b/docs/groups.md
@@ -81,6 +81,6 @@ require 'rocketchat'
 
 rocket_server = RocketChat::Server.new('http://your.server.address/')
 session = rocket_server.login('username', 'password')
-session.groups.upload_file(room_id: 'GENERAL', file: File, msg: "Optional Message", description: "Optional Description", tmid: "Optional thread message id")
+session.groups.upload_file(room_id: 'GENERAL', file: File, filename: "Optional. The name of the file to use.", content_type: "Optional. The content type of the uploaded file", msg: "Optional Message", description: "Optional Description", tmid: "Optional thread message id")
 
 ```
diff --git a/lib/rocket_chat/messages/room.rb b/lib/rocket_chat/messages/room.rb
index 7904d3c..7b6fa77 100644
--- a/lib/rocket_chat/messages/room.rb
+++ b/lib/rocket_chat/messages/room.rb
@@ -319,7 +319,7 @@ def upload_file(room_id:, file:, **rest_params)
         response = session.request_json(
           "#{API_PREFIX}/rooms.upload/#{room_id}",
           method: :post,
-          form_data: file_upload_hash(file: file, **rest_params)
+          form_data: file_upload_array(file: file, **rest_params)
         )
 
         RocketChat::Message.new response['message'] if response['success']
@@ -345,9 +345,17 @@ def validate_attribute(attribute)
           self.class.settable_attributes.include?(attribute)
       end
 
-      def file_upload_hash(**params)
+      def file_upload_array(**params)
         permited_keys_for_file_upload = %i[file msg description tmid]
-        Util.slice_hash(params, *permited_keys_for_file_upload)
+        hash = Util.slice_hash(params, *permited_keys_for_file_upload).compact
+
+        # NOTE: https://docs.ruby-lang.org/en/master/Net/HTTPHeader.html#method-i-set_form
+        file_options = params.slice(:filename, :content_type).compact
+        hash.map do |key, value|
+          next [key.to_s, value, file_options] if key == :file && file_options.keys.any?
+
+          [key.to_s, value]
+        end
       end
     end
   end
diff --git a/lib/rocket_chat/request_helper.rb b/lib/rocket_chat/request_helper.rb
index 5d75838..f280aa8 100644
--- a/lib/rocket_chat/request_helper.rb
+++ b/lib/rocket_chat/request_helper.rb
@@ -110,7 +110,7 @@ def create_request(path, options)
         req = Net::HTTP::Post.new(path, headers)
         add_body(req, body) if body
 
-        form_data = reject_nils(options[:form_data])
+        form_data = options[:form_data]
         add_form_data(req, form_data) if form_data
       else
         uri = path
@@ -131,7 +131,6 @@ def add_body(request, body)
     end
 
     def add_form_data(request, form_data)
-      form_data = form_data.transform_keys(&:to_s) if form_data.is_a? Hash
       request.set_form(form_data, 'multipart/form-data')
     end
 
diff --git a/spec/shared/room_behaviors.rb b/spec/shared/room_behaviors.rb
index 6bf6ef4..579e04c 100644
--- a/spec/shared/room_behaviors.rb
+++ b/spec/shared/room_behaviors.rb
@@ -724,6 +724,21 @@
       it { expect(upload).to be_a(RocketChat::Message) }
     end
 
+    context 'with content_type params' do
+      subject(:upload) { scope.upload_file(room_id: room_id, file: file, content_type: content_type, **rest_params) }
+
+      let(:content_type) { 'image/png' }
+      let(:file) { File.open('spec/fixtures/files/image.png') }
+      let(:response) { png_upload_response(room_id: room_id) }
+
+      before do
+        stub_authed_request(:post, path).to_return(body: response, status: 200)
+      end
+
+      it { expect { upload }.not_to raise_error }
+      it { expect(upload).to be_a(RocketChat::Message) }
+    end
+
     context 'when not accepted error is raised' do
       before do
         stub_authed_request(:post, path).to_return(body: response, status: 400)