While research on stalking has steadily expanded since 1990, there is still no conceptual model that explains stalking perpetration, stalking victimisation, and psychological reactions to stalking, such as fear, invasion of personal space and invasion of privacy. The aim of the thesis was to determine whether a situational model of stalking could assist an understanding of perpetration, victimisation and actual or anticipated psychological reactions to stalking. Whereas other theoretical approaches applied to stalking focus only on the offender, the situational approach focuses on physical and social environments that provide more opportunities for crimes to occur between particular victims and offenders. Applying the situational approach to stalking potentially allows for a greater understanding of how stalking occurs and whether environmental changes can be made to reduce criminal opportunities and deter criminal actions. The important components of the physical and social environments incorporated into the situational model of stalking tested in the thesis were stalkers and victims, their interpersonal relationships, the stalking actions engaged in by stalkers, the times and locations of stalking, and a lack of capable guardianship to stop the stalking from occurring. In the model it was proposed that particular stalkers engaged in actions against victims when certain locations and times provided opportunities to stalk, such as the absence of people who might intervene. As stalking also involves the psychological reactions of the victim, the associations between these situational elements and fear, invasion of personal space and invasion of privacy were included in the situational model of stalking.