There is not much difference between the two. In the United States, most people consider both of these terminologies interchangeable. A Walkie Talkie is a portable 2 way radio, which could be held in one’s hand. It is also called a handy transceiver.
On the other hand, a two way radio is a transceiver because it transmits and receives signals. 2-way radios even work in a half-duplex or a full duplex mode. The difference is that numerous two way radios are not handheld. So we can say that most of the two way radios are not always considered Walkie talkie, but all walkie talkies are always two ways radios.