TheRTiFe11Nxcompounds have higher Curie temperatures, larger saturation magnetization, and entirely different magnetocrystalline anisotropy behavior as compared with theRTiFe11compounds. In contrast toRTiFe11, thecaxis becomes the easy magnetization direction ofRTiFe11NxwhenR=Nd, Tb, Dy, and Ho, while SmTiFe11Nxhas an easy plane and ErTiFe11Nxpresents a spin reorientation at about 45 K. Theoretical calculations were made to explain those anisotropy behaviors. The calculation results show that the changes in anisotropy behaviors could be attributed to the large positive contribution of nitrogen atoms located at 2binterstitial sites to the second‐order crystal‐field coefficientA20.