To determine the relationship between slabbing failure and the specimen height-to-width (H/W) ratio and to analyze the conditions, characteristics, and mechanism of slabbing failure in the laboratory, uniaxial compression tests were conducted using six groups of granite specimens. The entire failure process was recorded using strain gauges and high-speed cameras. The initiation and propagation of fractures in specimens were identified by analyzing the monitoring results of stress, strain, and acoustic emission. The experimental results show that changes in the specimen H/W ratio can transform the macro failure mode. When the H/W ratio is reduced to 0.5, the macro failure mode is dominated by slabbing. Low load-bearing ability is observed in specimens with slabbing failure, and the slabbing fractures are approximately parallel to the loading direction. Moreover, the fracture propagation characteristics and acoustic emission signals of slabbing failure specimens show typical tensile failure characteristics, indicating that slabbing failure is essentially a special tensile failure.