A field experiment was conducted at Bilpar village of Sunamganj district in Bangladesh during November 2016 to May 2017 to find out the effects of Triple Super Phosphate (TSP) fertilizer on the growth and yield of boro rice in haor areas. Two factors viz. varieties (BRRI dhan29 and BRRI dhan58) and six TSP fertilizer levels [F1- 85 kg TSP ha-1 (Farmers’ practice), F2- 142 kg TSP ha-1, F3- 127 kg TSP ha-1, F4- 112 kg TSP ha-1 (BARC recommended dose), F5- 97 kg TSP ha-1, F6- 82 kg TSP ha-1] were included in the experiment. The experiment was conducted in the farmers’ field and laid out in a RCBD with three replications. Data were taken on plant height and tillers hill-1 at 15 days intervals. The yield and yield contributing parameters were also taken at harvest. Plant height, number of total tillers, effective tillers hill-1, panicle length, sterile spikelets, 1000 grain weight, grain and straw yield varied significantly due to variety. BRRI dhan58 produced higher number of effective tillers (10.60) and grains panicle-1 (136.9) over BRRI dhan29. BRRI dhan58 produced higher grain yield (8.92 t ha-1) compared to BRRI dhan29 (7.27 t ha-1). All the studied parameters differed significantly with the application of TSP fertilizer except non-effective tillers hill-1. Application of 112 kg TSP ha-1 produced the highest number of effective tillers hill-1 (12.00) and the lowest in farmers practice (7.20). Fertilizer Recommendation Guide based TSP fertilizer (112 kg ha-1) produced the highest grain yield (8.80 t ha-1) of boro rice and the lowest grain yield (7.40 t ha-1) in farmers’ practice. Results of the study elucidated that TSP application at 112 kg ha-1 was effective to improve the rice productivity.