Gene flow from transgenic rice to weedy and cultivated rice is a key biosafety consideration. This study assessed the gene flow from glufosinate-resistant (GR) transgenic hybrid rice (Oryza sativa L.) to six weedy rice (O. sativa) accessions and a rice cultivar (O. sativa) using three experimental designs: concentric circular, alternating cultivation and adjacent cultivation. Maximum gene flow from GR rice to the seven recipients (0.302 %) was found at 1 m from the pollen donor in the concentric circular experiment; the minimum rate was 0.011 % at 12 m from the pollen donor. For all recipients, gene flow frequency declined considerably with increasing distance from the pollen source. The maximum distance at which gene flow was detected was 14 m. A clear asymmetric distribution of hybrids was found with hybridization predominantly occurring in the recipient plants growing in the direction of the prevailing wind. Average gene flow frequency from GR rice to weedy rice ranged from 0.395 to 0.470 % and 0–0.187 % in the alternating and adjacent cultivation experimental designs, respectively. Overall, longer durations in flowering overlap between the pollen donor and the recipients resulted in increased gene flow. In addition to characterizing gene flow from GR transgenic hybrid rice to weedy and cultivated rice, this study provides considerable insight into the selection of a proper experimental design to evaluate gene flow, which is necessary for risk assessment and decision making regarding the possible deployment of transgenic hybrid rice.