Maize (Zea mays L.) is the highest produced crop in Ethiopia and plays a crucial role in ensuring food security in the country. However, its productivity is constrained by a number of problems, optimum plant population and nutrient management is the most critical as it is a heavy feeder. Therefore, this research was initiated at Bako to study the effect of NPSB rates and plant population on growth parameters and yield of maize. The field experiment was laid out in Split plot design distributing three levels of plant population [53,333 plants/ha (25cm x 75cm), 66,666 plants/ha (60cm x 25cm) and 76923 plants/ha (65cm x 20cm)] in the main plots and five levels of NPSB fertilizer rates (0,100,150,200 and 250 kg/ha) in sub-plots comparing with NP recommended rates in the research area. Plant population and NPSB rate did not change cob length, number of row cob-1. and harvest index. Interaction of plant population and NPSB rates influenced leaf area index, number of cobs per plot, number of kernels cob-1, above ground biomass and thousand kernel weight. Highest leaf area index 6.661 was recorded from interaction of 66,666 plants ha-1 and 200 kg NPSB. Highest number of cob plot-1 was recorded from the plot with 66,666 plants ha-1 and highest biological yield 28299kg/ha was harvested from the plot with standard check. Highest grain yield was obtained from 150 kg/ha with plant population of 66666 plants/ha (60cm x 25cm). Hence, it was concluded that fertilizer rates and plant population significantly affected the yield of maize, combination of 66,666 plant/ha and 150 kg/ha of NPSB fertilizer rate was found to be superior in yield and economically viable for maize production in the study area.