The nonlinear optical coefficients of lithium triborate LiB3O5(LBO) have been determined by the method of Maker fringes at &lgr;=1.079 &mgr;m. It is found that these coefficients relative tod36for potassium dihydrogen phosphate ared31=∓2.51 (l±0.09),d32=±2.69 (l±0.12),d33=±0.15 (l±0.10),d15=∓2.30 (l±0.22), andd24=±2.52 (l±0.20). The phase‐matching conditions, effective second‐harmonic generation (SHG) coefficients, walk‐off angles, and acceptance angles for SHG at &lgr;=1.079 &mgr;m are also investigated. The figures of merit of LBO in different cases are then compared with those of potassium dihydrogen phosphate (KDP), &bgr;‐barium metaborate (BBO), and potassium titanyl phosphate (KTP) crystals. All these figures combined with the damage thresholds of the crystals show that an LBO crystal may operate better than KDP and BBO crystals for frequency conversions of a tightly focused Nd:YAlO3(YAP) or Nd:Y3Al5O12(YAG) laser and also a dye laser.