diff --git a/lib/ews/connection.rb b/lib/ews/connection.rb
index edc4ab55..f5fc0e70 100644
--- a/lib/ews/connection.rb
+++ b/lib/ews/connection.rb
@@ -32,28 +32,15 @@ class Viewpoint::EWS::Connection
   #   seconds
   # @option opts [Array]  :trust_ca an array of hashed dir paths or a file
   # @option opts [String] :user_agent the http user agent to use in all requests
-  def initialize(endpoint, opts = {})
+  def initialize(auth, opts = {})
     @log = Logging.logger[self.class.name.to_s.to_sym]
-    if opts[:user_agent]
-      @httpcli = HTTPClient.new(agent_name: opts[:user_agent])
-    else
-      @httpcli = HTTPClient.new
-    end
 
-    if opts[:trust_ca]
-      @httpcli.ssl_config.clear_cert_store
-      opts[:trust_ca].each do |ca|
-        @httpcli.ssl_config.add_trust_ca ca
-      end
-    end
+    @httpcli = http_object(opts)
 
-    @httpcli.ssl_config.verify_mode = opts[:ssl_verify_mode] if opts[:ssl_verify_mode]
-    @httpcli.ssl_config.ssl_version = opts[:ssl_version] if opts[:ssl_version]
-    # Up the keep-alive so we don't have to do the NTLM dance as often.
-    @httpcli.keep_alive_timeout = 60
-    @httpcli.receive_timeout = opts[:receive_timeout] if opts[:receive_timeout]
-    @httpcli.connect_timeout = opts[:connect_timeout] if opts[:connect_timeout]
-    @endpoint = endpoint
+    @auth_type  = auth[:type]
+    @auth_token = @auth_type == 'oauth' ? auth[:token] : nil
+
+    @endpoint = auth[:endpoint]
   end
 
   def set_auth(user,pass)
@@ -99,8 +86,11 @@ def get
   # @return [String] If the request is successful (200) it returns the body of
   #   the response.
   def post(xmldoc)
-    headers = {'Content-Type' => 'text/xml'}
-    check_response( @httpcli.post(@endpoint, xmldoc, headers) )
+    headers = { 'Content-Type' => 'text/xml' }
+    if @auth_type == 'oauth' && @auth_token.present?
+      headers = headers.merge({ 'Authorization' => "Bearer #{@auth_token}" })
+    end
+    check_response(@httpcli.post(@endpoint, xmldoc, headers))
   end
 
 
@@ -137,4 +127,39 @@ def parse_soap_error(xml)
     [err_string, err_code]
   end
 
+  def http_object(opts)
+    @httpcli = if opts[:user_agent]
+                  HTTPClient.new(agent_name: opts[:user_agent])
+                else
+                  HTTPClient.new
+                end
+
+    trust_ca_option(opts)
+    ssl_config(opts)
+    timeout_options(opts)
+
+    @httpcli
+  end
+
+  def trust_ca_option(opts)
+    return if opts[:trust_ca].nil?
+
+    @httpcli.ssl_config.clear_cert_store
+    opts[:trust_ca].each do |ca|
+      @httpcli.ssl_config.add_trust_ca ca
+    end
+  end
+
+  def ssl_config(opts)
+    @httpcli.ssl_config.verify_mode = opts[:ssl_verify_mode] if opts[:ssl_verify_mode]
+    @httpcli.ssl_config.ssl_version = opts[:ssl_version] if opts[:ssl_version]
+  end
+
+  def timeout_options(opts)
+    # Up the keep-alive so we don't have to do the NTLM dance as often.
+    @httpcli.keep_alive_timeout = 60
+    @httpcli.receive_timeout = opts[:receive_timeout] if opts[:receive_timeout]
+    @httpcli.connect_timeout = opts[:connect_timeout] if opts[:connect_timeout]
+  end
+
 end
diff --git a/lib/ews/ews_client.rb b/lib/ews/ews_client.rb
index 2d0a43d3..e871c35a 100644
--- a/lib/ews/ews_client.rb
+++ b/lib/ews/ews_client.rb
@@ -39,16 +39,21 @@ class Viewpoint::EWSClient
   #   Viewpoint::EWS::SOAP::ExchangeWebService.
   # @option opts [Object] :http_class specify an alternate HTTP connection class.
   # @option opts [Hash] :http_opts options to pass to the connection
-  def initialize(endpoint, username, password, opts = {})
-    # dup all. @see ticket https://github.com/zenchild/Viewpoint/issues/68
-    @endpoint = endpoint.dup
-    @username = username.dup
-    password  = password.dup
-    opts      = opts.dup
+  def initialize(auth, opts = {})
+    auth = auth.dup
+
+    @auth_type  = auth[:type]
+    @auth_token = @auth_type == 'oauth' ? auth[:token] : nil
+
+    @endpoint   = auth[:endpoint]
+    @username   = auth[:user]
+    password    = @auth_type == 'basic' ? auth[:password] : nil
+
     http_klass = opts[:http_class] || Viewpoint::EWS::Connection
-    con = http_klass.new(endpoint, opts[:http_opts] || {})
-    con.set_auth @username, password
-    @ews = SOAP::ExchangeWebService.new(con, opts)
+    connection = http_klass.new(auth, opts[:http_opts] || {})
+    connection.set_auth(@username, password) unless password.nil?
+
+    @ews = Viewpoint::EWS::SOAP::ExchangeWebService.new(connection, opts)
   end
 
   # @param deepen [Boolean] true to autodeepen, false otherwise
diff --git a/spec/ews/ews_client_spec.rb b/spec/ews/ews_client_spec.rb
index 871d86c6..a80b4e9e 100644
--- a/spec/ews/ews_client_spec.rb
+++ b/spec/ews/ews_client_spec.rb
@@ -3,7 +3,7 @@
 describe Viewpoint::EWSClient do
 
   describe "#set_auto_deepen" do
-    let(:client) { described_class.new "http://www.example.com", "test", "test" }
+    let(:client) { described_class.new({endpoint: "http://www.example.com", type: "basic", user: "test", password: "test"}) }
 
     it "sets autodeepen to true on the web service" do
       ews = double "ews"
diff --git a/spec/unit/mailbox_accessors_spec.rb b/spec/unit/mailbox_accessors_spec.rb
index 5afacfe4..49b341d8 100644
--- a/spec/unit/mailbox_accessors_spec.rb
+++ b/spec/unit/mailbox_accessors_spec.rb
@@ -1,7 +1,7 @@
 require_relative '../spec_helper'
 
 describe Viewpoint::EWS::MailboxAccessors do
-  let(:ecli) { Viewpoint::EWSClient.new('dontcare', 'dontcare', 'dontcare') }
+  let(:ecli) { Viewpoint::EWSClient.new({endpoint: 'dontcare', user: 'dontcare', password: 'dontcare'}) }
   let(:recipients) { ['anyrecipient'] }
   let(:timezone_request) do
 "<t:TimeZone>
diff --git a/spec/unit/meeting_accessors_spec.rb b/spec/unit/meeting_accessors_spec.rb
index d2dd46e6..1cf8f9fc 100644
--- a/spec/unit/meeting_accessors_spec.rb
+++ b/spec/unit/meeting_accessors_spec.rb
@@ -1,7 +1,7 @@
 require_relative '../spec_helper'
 
 describe Viewpoint::EWS::MeetingAccessors do
-  let(:ecli) { Viewpoint::EWSClient.new('dontcare', 'dontcare', 'dontcare') }
+  let(:ecli) { Viewpoint::EWSClient.new({endpoint: 'dontcare', user: 'dontcare', password: 'dontcare'}) }
 
   let(:default_opts) do
     {