Willingness occupies a contested and pivotal position across the depth-psychology corpus, functioning simultaneously as a clinical construct, a spiritual virtue, and an existential stance. In Acceptance and Commitment Therapy literature — most fully elaborated by Russ Harris — willingness names the deliberate openness to experiencing unwanted thoughts and feelings rather than fleeing them; it is positioned as the antithesis of experiential avoidance and the necessary substrate of values-guided action. Dialectical Behavior Therapy draws a sharp diagnostic distinction between willingness and willfulness, treating the former as an adaptive orientation toward reality and the latter as rigid, emotionally escalating resistance — a polarity with immediate clinical utility. Twelve-Step and recovery literatures cast willingness in a different register altogether: here it is the essential moral and spiritual precondition for change, preceding confession, amends, and genuine transformation, and its absence is understood not as pathology but as volitional refusal. Irvin Yalom’s existential analysis complicates the picture further by mapping willingness onto the phenomenology of wishing and deciding, insisting that genuine willing requires both phases and that therapeutic errors arise from applying effortful second-realm volitional techniques to first-realm spontaneous processes. Robert Romanyshyn introduces an epistemological dimension, arguing that genuine witnessing demands not simply willingness to believe but the harder discipline of willingness not to disbelieve. Across these traditions, willingness emerges as the threshold capacity — the opening through which therapeutic movement, spiritual progress, and psychological integration first become possible.