Ignore all of the answers that talk about telnet not being secure, one of the problems with a client having the same name as the protocol (telnet, ftp). If they called it "connect", which used the "telnet" protocol, I'm guessing there'd be a lot less noise out there. But they didn't, now any time anyone talks about the telnet client, it gets conflated with the telnet protocol. It's definitely not even close to an answer for why it's not on MacOS right now. Simple answer: Download Putty, it's a great client that can do SSH, Telnet, and a lot of other things. Yes it stinks there's no "telnet" command but oh well, I've used SecureCRT for a long time (paid) and am very happy.