Background Cardiorespiratory system involvement and early fatigue observed in stroke patients complicate the rehabilitation process and affect their ability to perform daily activities and functional independence. Aim It was aimed to determine the relationship between respiratory functions and respiratory muscle strength with trunk control, functional capacity, and functional independence in hemiplegic patients after stroke. Materials and Methods Twenty‐five volunteers who were diagnosed with post‐stroke hemiplegia were included in the study. Sociodemographic and physical characteristics were recorded. Pulmonary function test (PFT), respiratory muscle strength, Trunk Impairment Scale (TIS), Timed‐Up and Go Test (TUG), and Barthel Index (BI) were applied. Results There was a moderate negative correlation between TUG scores and PFT results (r = 0.413–0.502; p = 0.011–0.04), except for PEF (%) and FEV1/FVC. Also, there were statistically significant correlation between TIS scores and FEV1(%) (r = 0.505; p = 0.012), FVC(%) (r = 0.449; p = 0.024). On the other hand, there was no statistically significant relationship between BI results and any parameter of the PFT (p > 0.05). There was no statistically significant correlation between respiratory muscle strength and TUG, TIS, BI (p > 0.05). Conclusion It has been shown that respiratory functions are associated with functional capacity and trunk control. However, it was found that there was no relationship between respiratory muscle strength and functional capacity, trunk control, and functional independence. It is thought that considering these parameters in the assessment of patients will contribute to the creation of individual and effective rehabilitation programs. The respiratory system should be systematically assessed in stroke rehabilitation and considered as part of a holistic approach. Clinical Trial Registration NCT05290649 (retrospectively registered) (http://clinicaltrials.gov).