This case study focuses on Grade 12 students aged 15 to 19 years in 2015/2016 in British Columbia, examining disparities in high school completion between students with and without disabilities and diverse abilities (DDAs). It looks particularly at those receiving a Dogwood Diploma (a certificate of graduation) or an Evergreen Certificate (a school completion certificate and not a graduation credential). Integrated administrative data from the Education and Labour Market Longitudinal Platform were used to disaggregate the high school completion paths of students with DDAs among six DDA categories (autism spectrum disorder, behavioural disabilities or mental illness, intellectual disabilities, learning disabilities, physical disabilities, and sensory disabilities) and compare them with those of students without DDAs. Results revealed that high school graduation disparities were larger than previously reported when considering students who were working toward an Evergreen Certificate. Students with DDAs (60%) were less likely to have graduated high school than students without DDAs (88%). The greatest disparities were observed among students with intellectual disabilities, who had the lowest high school graduation rate (6%) and, in turn, the highest likelihood of having received an Evergreen Certificate (51%). When accounting for sociodemographic factors, academic achievement played a crucial role in high school graduation, especially for students with behavioural disabilities or mental illness. This study highlights the importance of academic achievement for a successful high school completion path for all students--in particular for those with behavioural disabilities or mental illness--and the inclusion of students with DDAs on the Evergreen pathway to better understand high school completion paths of students with DDAs.