Posttraumatic growth (PTG) is the experience of positive psychological growth as a result of struggle with highly challenging life crises. This study was conducted to investigate the degree of PTG and its associated factors, as well as to identify which positive psychological parameters most significantly associated with greater PTG among Malaysian cancer patients. This cross-sectional survey included 195 patients with different cancer diagnoses. Perceived spousal support, level of hope, level of optimism, and PTG were measured using various validated indexes. The total mean score for PTG Inventory-Short Form (PTGI-SF) was 39.87 (±9.09). Female gender, Islamic religious belief, and having higher level of hope and greater spousal support were associated with a higher PTGI-SF score, and the most significant predictor was the hope scale. Malaysian cancer patients exhibited a high level of PTG, and hope was the positive psychological factor which was most significantly associated with PTG. Psychosocial interventions that promote positive psychology should be included in the treatment for cancer patients.