The present work is focused on experimental investigations of gas-liquid flows in T-junction splitting distributor for parallel micro-channels. The tree type T-junction splitting distributor was designed with four successive T-junctions (T1, T2, T3 and T4) that are linked in series to split a single main channel into four parallel channels. The design strategy was adopted from Adamson et al. , Hoang et al. , and modified with a combination of micro and milli channel dimensions and reduction in width of the successive blocks by a factor of 20.5 to ensure the flow uniformity in terms of constant relative lengths (Lbubble/slug/Wchannel) of bubbles/slugs in all the blocks. Experiments were performed to study the effect of Qoil (=3, 6, 8, 10, 12 and 16 ml/min) at fixed Qair (=3 ml/min) on formation dynamics of bubbles/slugs at 1st T-junction and splitting mechanisms of bubbles/slugs at the successive T-junctions, the corresponding relative lengths of bubbles/slugs and flow regimes. The results obtained from the present work showed that, followed by formation of parent gas slug at T1 the splitting of gas slug occurred at the successive T-junctions (T2, T3 and T4). Three types of splitting mechanisms were observed such as obstructed (Qoil = 3, 6, 8, 10 ml/min; 0.0023 ⩽CaBlock-I ⩽0.0050), partially obstructed (Qoil = 12 ml/min; CaBlock-I = 0.00585) and non-obstructed (Qoil = 16 ml/min; CaBlock-I = 0.0074). It was observed that asymmetry of the splitting at the successive T-junctions was reduced for Qoil ⩾10 ml/min (CaBlock-I ⩾0.0050). No splitting of bubble was observed for Qoil > 16 ml/min. However, it was also found that the proposed design strategy of splitting distributor for parallel micro-channels yields an almost constant relative lengths of bubbles/slugs (flow uniformity) in all the blocks for Qoil ⩾8 ml/min. © 2018 Elsevier B.V.