In the present investigation, the mechanical and microstructural characteristics of friction stir welded AA7020-O Al plates were investigated. The influence of the tool rotational and welding speeds such characteristics was studied. The friction stir welding (FSW) were conducted at tool rotational speeds of 1120, 1400, and 1800 rpm and at welding speeds of 20, 40 and 80 mm/min. It has been found that increasing the tool rotational speed and/or reducing the welding speed increases the primary Al phase grain size. It has been found that the tensile characteristics of the friction stir welded tensile samples depend significantly on both the tool rotational and welding speeds.