Background and AimsHypertension is the third leading cause of death in the world and is estimated to be increased by about 60% by 2025. Beliefs about hypertension can predict patient adherence to hypertension treatment. This study aims to investigate the perceptions of hypertension and adherence to hypertension treatment among patients in Khorramabad, Iran.MethodsThis is a descriptive/analytical study with a cross‐sectional design. Participants were 265 patients with a history of hypertension referred to a hospital in Khorramabad, Lorestan Province in western Iran in 2020, who were selected using a convenience sampling method. A demographic form, the brief illness perception questionnaire‐revised (BIPQ‐R), and Morisky medication adherence scale (MMAS‐8) were used for collecting data. The collected data were analyzed in SPSS v.22 software using descriptive statistics, Pearson's correlation test, independent t‐test, one‐way ANOVA, and regression analysis.ResultsThe mean scores of BIPQ‐R and MMAS‐8 were 49.05 ± 15.45 (out of 80) and 3.69 ± 1.62 (out of 8), respectively. There was a significant relationship between the mean scores of MMAS‐8 and BIPQ‐R in total (p < 0.001). Perceptions of illness consequences (B = 4.59, p = 0.005), personal control (B = 0.190, p = 0.047), and symptoms (B = 1.77, p = 0.005) could significantly predict treatment adherence of patients. In illness perception, there were significant differences among patients with different places of residence (p = 0.032), educational levels (p = 0.001), and employment status (p = 0.010). In treatment adherence, there were significant differences among patients with different places of residence (p = 0.042) and educational levels (p = 0.045).ConclusionTreatment adherence of hypertensive patients in western Iran is at a low level, while their perception of hypertension is at a moderate level. Clinical physicians are recommended to pay attention to the perception of illness in these patients (especially unemployed and less educated patients living in rural areas) to improve their adherence to treatment and blood pressure control.