Will I have any issues entering Thailand with a one-way ticket if I plan to travel to Cambodia afterward?

Travelers can enter Thailand with a one-way ticket as long as they can demonstrate that they will be leaving the country afterward. It's primarily the airline that will inquire about proof of onward travel when boarding, but once in Thailand, there are typically no further questions. If someone is already on a valid long-term visa (such as a DTV), they may not need to show a ticket at all.