During the last two decades, the cases of slope failures have soared in many parts of the world particularly in Malaysia as a result of rapidly expanding economic development, especially on hilly terrains. Extensive studies on previous slope failures unveil that, apart from rain, there are many factors that can instigate the failure in slopes. These contributing factors mainly include human errors such as lack of sufficient maintenance, incompetence during operations and incognizance of geological conditions. This study applies the tailored human error assessment and reduction technique (HEART) to determine the contributing factors of Malaysian landslides. HEART is widely used to analyse and quantify the human errors because it follows a straightforward approach that is not limited to a specific field. In this study, HEART is applied to determine the human error probability (HEP) of tasks and subtasks in the design, construction and maintenance phase of slope works that are vulnerable to human errors. An expert opinion is used for acquiring the data necessary for deducing the human error probabilities. For promoting improved slope engineering practices, this study proposes a theoretical framework to mitigate the chances of human errors in terms of slope stability. © 2017, Springer International Publishing AG.