Abstract: 1) Background: The present study aimed to examine the effect of the instructional intervention in family caregivers’ perceived threat of stroke patients’ dependency risk. 2) Methods: This was a randomized controlled clinical trial in which two patient and family caregiver groups of 45 were randomly divided into intervention and control groups based on the inclusion/exclusion criteria. Instructional intervention for family caregivers in the intervention group was in the form of four one-hour sessions. The data were collected before and immediately after instructional intervention at the hospital as well as two weeks and two months following the intervention via postal service. The data analysis was done using SPSS ver.22. 3) Results: The pre-intervention family caregivers’ perceived threat was not significantly different in the two groups (P = 0.591). However, the family caregivers’ perceived threat of the intervention group increased after the intervention compared with the control group (P < 0.001). In addition, the family caregivers’ perceived threat of the intervention group was significantly different in all post instructional intervention stages compared with pre-intervention (P < 0.001), whereas no such difference was observed in the control group (p = 0.245). 4) Conclusions: It is recommended that stroke patients' caregivers be provided with instructional programs to enhance their understanding of patient dependency risks and challenges.