Mangosteen fruit (Garcinia mangostana L.) is consumed mainly for two purposes, i.e., its aril for fresh or minimally processed products and its rind for herb and other health-related products. In fact, due to the high portion of rind compared to its whole fruit, its rind has a more important economic value, especially for its α-mangostin content. This study reported the effects of flower baggings on the α-mangostin content during mangosteen fruit growth. This field research was conducted in a farmer’s field at Gisting village, Tanggamus District, Lampung Province, Indonesia. The study was arranged in a 2 × 3 factorial design. The first factor was bagging date [2 and 4 weeks after anthesis (WAA)], and the second one was bagging material (unbagged or control, banana ‘Cavendish’- paper bag, and balloon). Fruit samplings were conducted in every two weeks during the periods of 8-16 WAA. The α-mangostin content was analyzed with HPLC [DionexUltiMate® 3000, autosampler, column compartment, Ultimate 3000 pump, UV detector, column Enduro C-18 (250 mm × 4.6 mm, 5 µm) with C18 guard]. The results showed that the α-mangostin content increased in a sigmoid pattern during fruit growth, and the increase was mostly not affected by bagging, bagging materials, and application periods. The α-mangostin content increased tremendously during 10-14 WAA, regardless of bagging, bagging materials and application periods. Bagging had resulted in the decrease of α-mangostin content during the latest period of fruit growth, regardless of bagging materials and application periods