This chapter offers an analysis of the range of shifting factors that impact upon Iran-Afghanistan relations. With the removal of US troops from Afghanistan, other factors will gain prominence and exert greater influence over the shape and direction of Iran-Afghan relations. Following an examination of bilateral relations in the wake of the Taliban's demise, the chapter focuses on the trajectory of Iran's approach. It argues that relations could improve significantly in the future, while noting that overarching Iranian concern about the US military presence has sometimes led to contradictory policies. The drawdown of US troops, the pragmatic leadership of Rouhani and the installation of a new president in Kabul, Ashraf Ghani, who appears intent on maintaining cordial relations with both Washington and Tehran, have shifted dynamics, largely in a positive direction. Afghanistan is important to Iran in that Afghan territory provides a venue for low-cost sabotage of US interests.