Aim Little is known about the reasons why tuberculosis (TB) service providers do not follow TB treatment guidelines. A better understanding of their real-world experiences associated with non-compliance with guideline may highlight opportunities for enhanced TB care. Whether the problem is actual or perceived may also affect the type of intervention needed to overcome the barrier. This study aimed to explore TB service providers' reasons for not complying with TB treatment guidelines. MethodA descriptive qualitative design was used. Focus group discussions were held with 39 service providers involved in TB care. The study was carried out in the Tigray region of Ethiopia, in four of the six zonal hospitals. Data were analysed using content analysis. ResultsThe main reasons for non-compliance with TB treatment guidelines were: (1) insufficient diagnostic modalities, limiting the capacity to correctly diagnose TB and provide the right regimen; (2) ambiguity in guideline recommendations especially for specific subgroups of patients, making it difficult to prioritize them to the right regimen; and (3) poor documentation concerning referred patients, with no appropriate examination and difficulty obtaining information from previously treated patients. ConclusionNon-compliance may reflect valid questions about the applicability of guideline recommendations in the local context of health care. Special consideration should be given to previously treated patients, as an important factor influencing guideline compliance. Guideline compliance may also be improved by a better strategy to retest those patients whose initial tests are negative in health care contexts where TB is frequently missed.