Background: Despite known benefits, cancer care systems struggle to provide early, integrated palliative care (PC). Previously, we identified barriers to providing early PC as perceived by gastrointestinal oncology clinicians in Alberta, Canada (top barrier: time/competing priorities). Here, we expand on the previous study to better understand barriers to early PC for clinicians working with all tumor groups across Alberta. Methods: A 33-item survey was emailed to oncology clinicians in Alberta between November 2017 - January 2018. Questions were informed by Michie’s Theoretical Domains Framework (TDF) and Behaviour Change Wheel (BCW) and queried (a) providing PC in oncology clinics, (b) referral to specialist PC consultation, and (c) working with PC consultants and homecare. Results: Respondents (n = 268) were nurses (42%), physicians (25%), and allied health professionals (20%). Barriers most frequently identified were "patients’ negative perceptions of PC” (68%), “my limited time/competing priorities” (66%), and "capability to manage patients’", social (65%) and spiritual (63%) concerns. These factors map to all three BCW domains: motivation, opportunity, and capability. In contrast, least frequently identified barriers were in clinician’s own motivation, e.g. perceived benefits of PC. There were few significant differences in response by tumor group or profession (χ² test, responses coded: disagree [1-3], neutral [4], agree [5-7]). Most notably, tumor groups differed in their perception that “the criteria for PC services are too restrictive” (p = 0.003), while nurses and allied staff reported that patients’ negative perception of PC is a barrier more frequently than physicians (p = 0.003). Conclusions: Surveying across clinicians and tumor groups using Michie’s TDF/BCW revealed that the challenges to an early integrated PC approach include all three sources of behavior, though not equally for all clinicians. Determining this has allowed us to tailor multifaceted interventions, e.g. tip sheets to enhance capability, re-framing PC with patients, and earlier secondary PC nursing access, to enhance clinicians use and patients benefit from an early PC approach.