Youths' experiences in seeking and accessing help for mental health problems can have pervasive and lasting effects on personal and interpersonal functioning. In particular, youth who experience validating experiences presumably persevere in seeking help and generally have positive treatment outcomes, whereas youth who experience invalidation are also likely to experience, at least in the short term, ruptures in therapeutic relationships, shame, and reluctance to seek services. The goal of the current study was to expand on previous research assessing youths' interactions with mental health providers, allied professionals, family members, and peers, with a focus on subjective experiences of validation and invalidation. The current study investigated both validating and invalidating experiences in seeking, accessing, and maintaining professional services among 31 Canadian youth (n = 20 girls, n = 11 boys; 12 to 21 years old [M = 16.97, SD = 2.01]) who were diagnosed or self-identified with at least one of five conditions: depression (n = 26), anxiety (n = 22), eating disorders (n = 9), autism spectrum disorder (n = 2), or conduct disorder or oppositional defiant disorder (n = 2). Youth were recruited using convenience (e.g., posted advertisements in mental health clinics) and snowball sampling methods. Journey mapping methodology (i.e., participants created visual representations of milestones of their mental health journeys) was employed accompanied by semi-structured interviews to prompt youth to expand on their experiences (e.g., Could you describe what was happening in your life when you first felt you would need support for your mental health?). Four themes emerged using inductive thematic analysis, marked by the presence (validation) or lack (invalidation) of: feeling heard, feeling seen, feeling understood, and receiving helpful actions. Participants also reported key consequences of validation and invalidation. Findings broaden a conceptualization of validation across supportive relationships and an understanding of factors that enhance or impede the formation or maintenance of therapeutic relationships with youth. Clinical implications and limitations are discussed.