Negotiations performed through videoconference have traditionally been studied in comparison to other communication media such as face-to-face, audio channels, or instant messaging. In this systematic literature review, we aim at gathering all empirical studies of buyer-seller negotiations performed synchronously by two people using a video system, analyzing the variables studied and the technological evolution of video negotiations. We develop a framework to classify the relevant variables, dividing them into negotiation, communication, and technological variables, and also in objective or subjective variables. We find that there are mixed or inconclusive results concerning negotiation variables such as economic outcomes, negotiation time, satisfaction, power, or trust. Technological variables like screen size, hardware and software used or user familiarity with technology show the evolution of videoconferencing and are very different among studies, which hinders its comparability. Emerging technologies involving extended reality or artificial intelligence may change the game in the negotiation world.