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In Malaysia, Perlis is known as one of the main states for mango production specifically the Harumanis variety since it has a unique taste as compared to other types of mangoes. Nevertheless, due to unfavourable climatic condition such as unpleasant raining and windy season, the production of Harumanis decreased extremely. Mangifera indica cv. Harumanis is a fruit crop that require hot weather in order to have high yielding. Unfortunately, the occurrence of heavy rain had prevented the production by causing flowers to fall off before pollination begin. Hence, the application of plant growth regulator paclobutrazol (PBZ) was used to induced the flowering of Harumanis mango crops and enhance their vegetative growth. This experiment took place at the research plot in Unit Ladang UiTM Perlis Campus Arau starting from the first week of September 2023 using the Complete Randomized Block Design (CRBD). A total of 32 trees of 3 years old Harumanis mango trees were drenched with four different concentrations of PBZ hormone (T1: control without treatment, T2: 5 mL L-1/tree of PBZ, T3: 10 mL L-1/tree of PBZ, and T4: 15 mL L-1/tree of PBZ). The number of leaves, number of new leaves, length of stems, formation of new bud, chlorophyll concentration, stomatal density, total leaf area, number of panicles, length of panicles, width of panicles, and number of matured panicles are the instances of parameters that were observed weekly. The vegetative parameters have significant difference between concentrations since number of new leaves produced was the highest with 10 mL L-1/tree of PBZ. Besides, most trees with 5 mL L-1/tree of PBZ, 10 mL L-1/tree of PBZ, and 15 mL L-1/tree of PBZ produced flowers 6 weeks after PBZ application. In conclusion, PBZ application positively influenced the flowering and physiological characteristics of Harumanis trees by stimulating off-season flowering.