We study cross-tier legislative incumbency spillovers in non-concurrent elections, a relatively understudied dimension of multi-level electoral politics in federal systems. Using a regression discontinuity design with comprehensive election data from India covering parliamentary elections (1999–2019) and state assembly elections (1994–2023), we find significant bidirectional negative spillovers. Having an incumbent member of parliament reduces the probability of that party’s candidate winning in subsequent state assembly elections by 7.2 percentage points (or by 17.6%), within that parliamentary constituency (Top-down spillover). Similarly, having an incumbent Member of the Legislative Assembly reduces the party’s vote share in subsequent parliamentary elections by 2.4 percentage points (or by 6.5%), in that assembly constituency (Bottom-up spillover). Effects are concentrated among centralized parties, non-switching candidates, and both ruling and opposition parties. Spillovers are stronger in less developed states and when elections occur within 2.5 years of each other.