In follicular lymphoma (FL), progression of disease ≤24 months (POD24) has emerged as a prognostic marker for overall survival (OS). We aimed to investigate OS broadly by timing of progression and treatment in a population-based setting. A total of 948 stage II-IV indolent FL patients, diagnosed 2007-2014 and treated with first-line systemic therapy, were identified in the Swedish Lymphoma Register and followed through 2020. Hazard ratios (HRs) with 95% confidence intervals (CIs) were estimated by first progression of disease at any time during follow-up (POD) using Cox regression. OS was predicted by POD using an illness-death model. During a median follow-up of 6.1 years (range: 0-10), 414 patients experienced POD (44%), of which 270 (65%) occurred ≤24 months. Compared with patients in remission, POD increased all-cause mortality across treatment groups, but less so among patients treated with rituximab(R)-single (HR=4.54, 95% CI: 2.76-7.47) than R-chemotherapy (HR=8.17, 95% CI: 6.09-10.94). The negative impact of POD on survival remained for progressions up to five years after R-chemotherapy, but was restricted to the first two years after R-single. To conclude, progression of disease beyond 24 months is associated with worse survival, illustrating the need for individualized management for optimal care of patients with FL.