Unspoiled wildlands of boreal landscapes provide critical habitats for wildlife. With the increase in resource development across Canada's boreal zone, woodland caribou (Rangifer tarandus caribou) and grizzly bears (Ursus arctos) are at risk of population declines. We used 4 planning scenarios with variants of these in decision-support software Marxan to allocate potential conservation priority areas for caribou and grizzly bears in boreal wildlands of the Muskwa-Kechika Management Area in northeast British Columbia, Canada. For caribou and grizzly bears across their seasonal habitats, priority areas allocated to preserve connectivity of habitat patches maintained more intact high-value habitats, with moderate opportunity cost for resource development, than those allocated under other scenarios. In winter when high-value habitats of caribou tend to coincide with resource-rich areas, priority areas allocated to preserve areas that are more vulnerable to development maintained more intact high-value habitats with higher opportunity cost (therefore greater adverse economic consequences) than those allocated in areas with lower resource potential. In growing-season (non-winter) habitats of caribou and grizzly bears, allocating priority areas toward either more vulnerable or less vulnerable areas did not substantially affect patch and landscape characteristics of conserved habitats. Priority areas intended to avoid predation risk for caribou were not effective in maintaining intact high-value habitats for caribou in these undeveloped wildlands. Conserving connectivity would best maintain most intact habitats for both species across seasons; conserving habitats most vulnerable to development also would discourage future development outside of the conserved areas in winter habitats of caribou. Findings from these conservation planning scenarios have implications globally to other areas where sensitive species are threatened by pending resource developments.