Insulin therapy in diabetes mellitus imposes burdens including limited lifestyle flexibility, difficulty achieving glycemic targets, and dissatisfaction with delivery devices. This study aimed to assess insulin-treated patient experiences using the Insulin Treatment Satisfaction Questionnaire (ITSQ) and to identify key predictors impacting patient experiences. We conducted a cross-sectional survey of 220 insulin-treated adults at primary healthcare clinics across the West Bank, Palestine. The subscale scores were 68.8% ± 26.6% for regimen inconvenience, 68.3% ± 28.1% for lifestyle flexibility, 58.0% ± 18.7% for glycemic control, 62.2% ± 21.0% for delivery-device satisfaction, and 72.3% ± 16.5% overall ITSQ score. Multiple linear regression was used to explore associations between ITSQ domains and candidate predictors. Delivery-device satisfaction was independently lower among female patients (β = - 0.18, p = 0.007) and in those with type 2 diabetes (vs. type 1; β = - 0.14, p = 0.037). Overall ITSQ total scores were on average 11.0% higher in diet-adherent patients (β = 0.31, p < 0.001). Insulin-treated patients reported suboptimal satisfaction influenced predominantly by diabetes type, dietary adherence, and delivery mode, underscoring the need for targeted interventions such as flexible meal planning, expanded pen access, and enhanced adherence support to improve experiences and reduce complications, warranting further research.