The growing literature conceptualizing mental disorders like Posttraumatic Stress Disorder (PTSD) as networks of interacting symptoms faces three key challenges. Prior studies predominantly used (a) small samples with low power for precise network estimation, (b) non-clinical samples, and (c) single samples. This renders network structures in clinical data, and the extent to which networks replicate across datasets, unknown. To overcome these limitations, the present cross-cultural multisite study estimated regularized partial correlation networks of 16 PTSD symptoms across four datasets of traumatized patients receiving treatment for PTSD (total N=2,782), and compared resulting networks.Despite differences in culture, trauma-type and severity of the samples, considerable similarities emerged, with moderate to high correlations between symptom profiles (0.43 to 0.82), network structures (0.62 to 0.74), and centrality estimates (0.63 to 0.75). We discuss the importance of future replicability efforts to improve clinical psychological science, and provide code, model output, and correlation matrices to make the results of this paper fully reproducible.