This article investigates the effects of Covid-19 on the network structure of BIST 100 firms. Analysis are carried out with filtered daily volatilities. Even after filtering out common factors, correlation and autocorrelation heat maps of the filtered volatilities indicate that there are still some patterns. Granger and contemporaneous type volatility networks are estimated and visualized for both the pre-Covid-19 and Covid-19 periods to determine the network structure differences. The article shows that there are centrality-type structures in the Granger network and chain-type linkages in the contemporaneous network for the pre-Covid-19 periods. The degree of interconnectedness is multiplied three times in the Granger network and eight times in the contemporaneous network with Covid-19.