Let \( G \) be a simple graph. The Euler Sombor index of \( G \) is defined as \begin{equation*} {\label{fi}}EU(G)=\sum_{xy\in E(G)}\sqrt{d_{G}^{2}(x)+d_{G}^{2}(y)+\left(d_{G}(x)d_{G}(y)\right) }, \end{equation*} where \( d_{G}(x) \) denotes the degree of the vertex \( x \), and the sum runs overthe set of edges of \( G \). In this paper we determine the extremal values of Euler Sombor index of tricyclic graphs.