No‐tillage maize (Zea mays L.) grown without adequate N intercepts less than 95% of the incident radiation at flowering. Reducing the distance between rows could increase radiation interception and grain yield. A 2‐yr experiment was conducted at INTA Research Station, Balcarce, Argentina (37°45′ S; 58°18′ W), to study the effect of row spacing and N availability on intercepted radiation, kernel number, and grain yield of no‐till maize. Treatments consisted of a factorial combination of row width (0.35 and 0.70 m) and N (0 and 120 or 140 kg ha−1 each year) at a constant plant density. Low N decreased kernel number and grain yield. Narrow rows significantly increased kernel number per unit area and grain yield. Average increases in response to narrow rows were 14.5 and 20.5% for kernel number and grain yield, respectively. However, relative increases in response to narrow rows were greater at low N. A close association between kernel number and intercepted radiation during the bracketing–silking period was observed. With conventional row spacing, relative grain yield responses to narrower rows decreased as crop radiation intercepted at flowering increased. A decrease in row distance when N was limiting partially offset the negative effects of N deficiency on grain yield. Our results indicate that 27 to 46% increases in grain yield were obtained in response to narrow rows in N‐deficient maize crops.