Boron (B) is a vital micronutrient that many crops, including vegetables, require in small amounts. However, brassica vegetables need B in higher doses. Although Chitwan has the highest area under cauliflower production, the productivity is low as a result of inadequate B fertilization. Cauliflower is a B-sensitive crop, and low B in soil results in poor growth, yield, and yield-related parameters. So, to study the growth, yield, and yield-related response of cauliflower varieties due to different B levels, a field experiment was conducted at the horticulture farm of Agriculture and Forestry University of Chitwan, Nepal. The experiment was laid out in a two-factor factorial randomized complete block design (RCBD) having (B levels: 0.55 kg ha−1, 1.1 kg ha−1, 1.65 kg ha−1, and 2.2 kg ha−1) and (cauliflower varieties; Kathmandu Local, White Top, and Snow Crown), which were replicated thrice. The maximum values of growth parameters like the plant height, leaf length, leaf breadth, plant canopy diameter, and the number of leaves were obtained from B 2.2 kg ha−1. Similarly, the White Top variety produced the tallest plant, the longest leaf, and the highest number of leaves, while the broadest leaf and canopy cover were observed in Snow Crown. The shortest days required for first, 50 % and 100 % curd initiation were observed in B 2.2 kg ha−1, and in the case of varieties, White Top took the least time for first, 50 %, and 100 % curd initiation. Similarly, the highest curd weight, curd diameter, and curd yield were obtained when B was applied at 2.2 kg ha−1. White Top produced the curd with the highest weight, diameter, and yield. A strong positive correlation was observed between curd diameter and leaf length (r = 0.89, p < 0.01) and curd diameter and leaf breadth (r = 0.84, p < 0.01). Curd yield and diameter were also positively correlated with r = 0.78 at p < 0.01. Thus, according to the current findings, it can be recommended that in the mid-season condition at Chitwan, Nepal, application of B at the rate of 2.2 kg ha−1 and the use of the White Top variety should be made for better growth and yield of cauliflower. Display omitted •Boron is an essential micronutrient for the growth, yield, and quality of crops including vegetables.•Brassica vegetables require boron in higher amount as compared to other crops.•Growth and yield parameters of cauliflower are severely influenced due to less boron use that ultimately reduces curd yield.•Boron at the rate of 2.2 kg ha −1 and the choice of White Top variety is therefore suggested in the mid-season condition at Chitwan, Nepal.