The study investigates the tail-risk spillover between the markets for sukuk and conventional bonds across fifteen countries between 2016 and 2023. First, we estimate a time varying parameter-value at risk (TVP-VAR)-based frequency connectedness model to measure the total, short-, and long-term frequency connectedness, which address the varying investment horizons of different investors. The connectedness in the sukuk market is smaller at all frequencies than in the bond market, which might offer investors better opportunities for diversification. Dynamic total connectedness fluctuates over time, which proves that connectedness is time varying and event dependent. The Covid-19 crisis and the Russia-Ukraine war are the main periods when connectedness intensified with high uncertainty. The results of this study offer insights for investors who seek diversification opportunities and policy makers especially during uncertain economic conditions.