AZ91, AZ91-0.5B and AZ91-1.0B magnesium alloys are produced in an inert atmosphere to investigate the influence of B on microstructure and properties of AZ91 alloy. Microstructural study is carried out using optical microscopy. Microhardness measurements are conducted by Vickers hardness tester. Using a pin-on-disk type apparatus, wear tests are conducted under dry sliding condition to assess the beneficial effect of boron on the wear properties of AZ91 alloy in relation to the resulted hardness and microstructures. The worn surface and wear particles morphology are also investigated. It is observed from microstructural investigation that the grains become finer with the addition of boron. The hardness is also found to increase with the addition of boron in AZ91 alloy, however maximum hardness is achieved with the addition 0.5 % B addition. The wear resistance is found to be better in the boron added alloy and maximum resistance is found with the addition of 0.5 % B. Wear mechanisms are also investigated.