Policy discourse about disinformation focuses heavily on the technological dimensions of state-sponsored disinformation campaigns. Unfortunately, this myopic focus on technology has led to insufficient attention being paid to the underlying human factors driving the success of state-sponsored disinformation campaigns. Academic research on disinformation strongly suggests that belief in false or misleading information is driven more by individual emotional and cognitive responses — amplified by macro social, political and cultural trends — than specific information technologies. Thus, attention given to countering the distribution and promulgation of disinformation through specific technological platforms, at the expense of understanding the human factors at play, hampers the ability of public diplomacy efforts countering it. This article addresses this lacuna by reviewing the underlying psychology of three common types of state-sponsored disinformation campaigns and identifying lessons for designing effective public diplomacy counter-strategies in the future.