Greening employment is required to avoid multiple ecological crises but so far there exist different notions of what makes a job ecologically sustainable. The article portrays five theoretical perspectives and develops a framework to evaluate the environmental impact of employment in four dimensions: (1) output type: sustainable goods and services as the outputs from work, (2) occupation: green tasks and activities at the workplace, (3) work-lifestyles: working conditions that promote workers' sustainable lifestyles, (4) outcome efficiency: resource-light production processes. It discusses previous approaches in each dimension and proposes improved assessment methods. By connecting the four dimensions, it develops a “Taxonomy of Sustainable Employment” to classify employment into green, mixed and brown jobs. The taxonomy can be applied to evaluate the sustainability of employment and identify effective labour market policies for a just transition.