This is just an FYI as I couldn't find any documentation on how to do this specifically for Twilio. To enable caller id name lookup using Twilio SIP trunks, you need to first enable it on their site. It currently costs $0.01 (1 cent) per call. They have a link on how to do this: https://www.twilio.com/blog/2017/11/elastic-sip-trunking-supports-cnam-lookup.html This change is immediate. So far, fairly easy.... Next you need to edit the 3CX SIP Trunk Inbound Parameters. The default template when you setup the twilio trunk doesn't have the name field mapped because this is an optional feature. You need to change the: "CallerName" caller's name (default: From->display name) To the value of: From: Display Name It was this last part that I wasn't sure of. Once I made this change, it started working.