Abstract: OBJECTIVE: To compare the course of change in individual posttraumatic stress disorder (PTSD) symptoms during prolonged exposure therapy (PE) and cognitive processing therapy (CPT). METHOD: We analyzed data from a previously published randomized clinical trial comparing PE and CPT among male and female U.S. military veterans with PTSD (Schnurr et al., 2022). Using data from a self-rated PTSD symptom measure administered before each therapy session, we evaluated individual symptom change from pretreatment to final therapy session (N = 802). Then, using network intervention analysis, we modeled session-by-session PTSD symptom networks that included treatment allocation (CPT vs. PE) as a node in the networks, allowing us to compare individual symptom change following each session in each treatment. RESULTS: Relative to CPT, PE was associated with greater reduction in 10 PTSD symptoms from first to final session of therapy. Numerous treatment-specific effects on individual symptoms emerged during the treatment period; these session-level effects occurred only in symptoms relatively specific to the diagnosis of PTSD (e.g., avoidance, hypervigilance). PE was associated with greater reduction in avoidance following the introduction and early weeks of imaginal exposure. The treatments yielded comparable effects on trauma-related blame and negative beliefs from pretreatment to final therapy session. However, there were differences in session-level change in these symptoms that may reflect differential timing of interventions that reduce distorted cognitions within each treatment. CONCLUSIONS: Findings may facilitate the shared decision-making process for patients choosing between CPT and PE. Session-level results provide direction for future research on the specific intervention components of CPT and PE.