Abstract: Boron deficiency is prevalent in soils with low activity clay. This study was carried out to determine the response of three cultivars of sunflower (Helianthus annuus L.)-Record, Isaanka and Funtua to boron fertilizer. Four levels of boron-0, 4, 8 and 12 kg B ha-1 were applied and the experimental design was randomized complete block with 3 replications. Results obtained showed that there were cultivar differences in response to boron fertilizer. Record variety recorded the highest plant height at 8 kg B ha-1 while Funtua have the highest seed yield at 4 kg B ha-1. The highest percentage oil content was recorded by Isaanka variety. Toxicity symptoms and reduction in yield were observed at the highest level B (12 kg B ha-1) in all the varieties. Percentage oil content correlated with capitulum diameter and seed yield. Regression analysis also revealed that the optimum B rate for the three cultivars and four years of trial for the various parameters determined ranged from 5.60-8.40 kg B ha-1.