diff --git a/lib/mail/message.rb b/lib/mail/message.rb
index a7318f844..5df6a2fe9 100644
--- a/lib/mail/message.rb
+++ b/lib/mail/message.rb
@@ -1918,7 +1918,7 @@ def decode_body
     # Returns true if this part is an attachment,
     # false otherwise.
     def attachment?
-      !!find_attachment
+      !!(content_disposition == "attachment" || find_attachment)
     end
 
     # Returns the attachment data if there is any
diff --git a/spec/fixtures/emails/attachment_emails/attachment_without_a_filename.eml b/spec/fixtures/emails/attachment_emails/attachment_without_a_filename.eml
new file mode 100644
index 000000000..cfe426908
--- /dev/null
+++ b/spec/fixtures/emails/attachment_emails/attachment_without_a_filename.eml
@@ -0,0 +1,28 @@
+MIME-Version: 1.0 (Apple Message framework v730)
+Content-Type: multipart/mixed; boundary=Apple-Mail-13-196941151
+Message-Id: <9169D984-4E0B-45EF-82D4-8F5E53AD7012@example.com>
+From: foo@example.com
+Subject: testing
+Date: Mon, 6 Jun 2005 22:21:22 +0200
+To: blah@example.com
+
+
+--Apple-Mail-13-196941151
+Content-Transfer-Encoding: quoted-printable
+Content-Type: text/plain;
+	charset=ISO-8859-1;
+	delsp=yes;
+	format=flowed
+
+This is the first part.
+
+--Apple-Mail-13-196941151
+Content-Type: text/x-ruby-script;
+Content-Transfer-Encoding: 7bit
+Content-Disposition: attachment;
+
+puts "Hello, world!"
+gets
+
+--Apple-Mail-13-196941151--
+
diff --git a/spec/mail/attachments_list_spec.rb b/spec/mail/attachments_list_spec.rb
index 0f5245404..73d5f5150 100644
--- a/spec/mail/attachments_list_spec.rb
+++ b/spec/mail/attachments_list_spec.rb
@@ -279,6 +279,12 @@ def check_decoded(actual, expected)
       expect(mail.attachments.first.filename).to eq "ciële.txt"
     end
 
+    it "should decode an attachment without a filename" do
+      mail = read_fixture('emails/attachment_emails/attachment_without_a_filename.eml')
+      expect(mail.attachments.length).to eq 1
+      expect(mail.attachments.first.filename).to eq nil
+    end
+
     it "should find attachments inside parts with content-type message/rfc822" do
       mail = read_fixture('emails/attachment_emails/attachment_message_rfc822.eml')
       expect(mail.attachments.length).to eq 2