In this work, flame spread experiments with the flow applied in the opposite to the direction of spreading flame are conducted using 80 mm long cast PMMA cylinders of 1 mm diameter in the earth’s gravity and microgravity environments. The experiments are conducted at 23% of oxygen by volume in nitrogen at one atmospheric pressure with no flow condition (0 cm/s) and flow speed of 25 cm/s. Flame spread rate, and flame shapes are analyzed by processing the images captured using a digital camera. A unique mushroom shape flame is obtained in microgravity condition which is different from the rounder shape flame observed by previous researchers. The flames spread rates are higher in microgravity condition compared to the flame spread rates in earth’s gravity condition and the spread rate is lesser at higher applied flow speed. To understand the details of the flame spread phenomenon, CFD simulations are carried out using an in-house 2D-axisymmetric flame spread solver. The flow field in earth’s gravity and microgravity are quite different. In earth’s gravity the buoyancy accelerates the flow and entrains surrounding air into the flame, which is absent in microgravity condition. This difference in flow field affects heat and mass transport processes in the flame and hence size and spread rate of flames. These details are discussed in detail in the article.