The ‘Greening of Religion’ (GoR) hypothesis purports that, through some combination of critical momentum and ecological necessity, faith communities have undergone a transformation towards ecologically friendly thought and practice. To date, this claim has primarily been tested using attitudinal data, with less regard for tangible actions occurring within places of worship. This research analyzes environmental activism in places of worship across the Greater Toronto Area (GTA), based on self-published web content. The project catalogues the depth and extent of faith-based environmentalism among each group, thereby facilitating comparative analysis and establishing a baseline for longitudinal evaluation of the ‘Greening of Religion’ hypothesis. A new dataset was created by gathering environmental content shared online by places of worship belonging to major faiths in the GTA (n = 1806). The raw data was coded into 4 overarching categories of environmental activity: Worship, Community, Operations, and Environmental Justice — each containing numerous action types. The data was subjected to tabulation and chi-square analysis to assess differences between and within each community. The analysis shows substantive interfaith differences in the extent, depth, and focus(es) of environmental action. Though a diverse range of action was observed, only 23.5% of places of worship were observed undertaking these initiatives. Though not negligible, environmentalism is clearly not yet a primary concern of the region’s faith communities. However, the diversity and extent of environmentalism documented provides valuable insights in its own right, while faith-specific analyses suggest points of departure for targeted research. Notably, Mainline Protestant, Jewish, and Buddhist communities all showed extensive environmental activity compared to other faiths. This research develops a novel approach to evaluating faith-based environmental action at a large scale, and establishes a necessary baseline for evaluating the GoR hypothesis. Capturing both explicit and implicit environmentalism likewise advances a more complete approach to evaluating environmental action. The study’s findings are revealing, but also stimulate discussion of confounding factors that content analysis cannot capture — socioeconomic, theological, and otherwise — as topics for further research.