Tuberculosis (TB) incidence is decreasing in the Northern Territory (NT) but still exceeds rates elsewhere in Australia. Deaths and morbidity from advanced TB continue, with delay in diagnosis a contributor to adverse outcomes.We aimed to describe the delay in diagnosis of TB, identify risk factors for delay and examine the associations between delay and clinical outcomes.We conducted a historical cohort analysis which included adult inpatients diagnosed with TB at the Royal Darwin Hospital from 2010 to 2020. Patient delay was measured as time from symptom onset to first seeking care, and health system delay was quantified as time from first relevant clinical contact to diagnosis. The sum of these two periods was the total delay. Ethics approval was granted by NT HREC (2020-3852).Eighty-four cases were included; the median total delay was 90 days (interquartile range (IQR): 60-121), patient delay was 53 days (IQR: 30-90), and health system delay was 21 days (IQR: 12-45). Patient delay was longer among patients with extrapulmonary (median: 100 days (IQR: 90-105) compared with pulmonary TB patients (39 days (IQR: 27-54), P < 0.0001). Health system delay was longer in those aged ≥45 years (30 days (IQR: 16-51) vs younger patients (14 days (IQR: 8-30), P = 0.007) and among non-smokers (31 days (IQR: 21-55) vs 21 days (IQR: 10-40), P = 0.048). Median delay was longer among patients with non-drug-related complications of disease (P < 0.0001), those admitted to critical care (P < 0.0001), and those with respiratory failure (P = 0.001).The patient delays we report are longer than reported elsewhere in Australia. The next steps will require concerted efforts to improve community awareness of TB and strategies to strengthen health systems through better resourcing and healthcare provider support.