The current situation in Afghanistan involves internal conflict with the Taliban group, who have managed to gain control of the country. Therefore, the author formulates the problem: What is the Influence of the power transition in Afghanistan to the Taliban on the security of the South Asia region in 2020-2021? The objective of this study is to gain insight into and examine the power transition in Afghanistan, which was previously overseen by President Ashraf Ghani and is now under the authority of the Taliban. The study utilises two theories: The Power Transition theory and the Regional Security theory. According to the findings of this study, it is evident that the government under Ashraf Ghani's leadership exhibited significant weaknesses. Consequently, following the departure of US and NATO forces, Afghanistan faced a void in governance that the Taliban capitalised on, resulting in their control over multiple regions, including the capital city of Kabul.