Applications of Mg-Al alloys are continually increasing, prompting the need to understand the corrosion behavior of these materials in loading conditions. This paper considers the effect of cerium additions on the stress corrosion cracking in the Mg-Al-Zn alloy AZ91D. The addition of cerium is thought to improve the corrosion performance of AZ91 alloys through microstructural modifications. Immersion, potentiostatic polarization, and slow strain rate testing (SSRT) of AZ91D and AZ91D+Ce alloys are used to explore the influence of cerium on stress corrosion cracking behavior in AZ91D.