Micropitting is a type of wear mechanism that has drawn the attention of many researchers. It has been proved that surface roughness has a great influence on micropitting initiation. How to factor in surface roughness in micropitting prediction is still under investigation. In this paper, the surface roughness and safety factor against micropitting are utilized in gear micropitting prediction in FZG gear tests. Firstly, the tooth profile was measured in situ in the FZG gear micropitting test using a profilometer. Wear along the tooth profile was evaluated by least-squares fitting of the measured profiles to the nominal shape. Based on the distributed quantitative tooth surface wear depth, the wear coefficient curve along the tooth profile was calculated according to Archard’s wear law. Secondly, for each point on the tooth profile, the local arithmetical mean surface roughness of the assessed profile was computed within the Hertzian contact area. By adapting the safety factor calculation method according to ISO 6336, the local safety factor against micropitting was determined. Lastly, the wear depth along the gear tooth profile was predicted based on Archard’s wear law. Micropitting prediction for gears made from wrought steel and powder metallurgy was conducted to validate the proposed method. The results demonstrate that micropitting can be predicted by utilizing the concept of local surface roughness and surface safety factor against micropitting.