Adoption is a complex path to fulfilling the parenting role that confronts mothers with numerous identity challenges. The present study aimed to deeply explore the identity transition process of adoptive mothers and understand how they navigate from initial idealism toward redefining the concept of parenting. This qualitative study was conducted using thematic analysis. Through purposive sampling, eight adoptive mothers in Tehran (2024-2025) were selected. Data were collected using in-depth semi-structured interviews and analyzed based on Braun and Clarke’s approach. Exploring the lived experiences of the participants led to the identification of four main themes: “idealistic beginnings,” “encountering reality,” “redefining the boundaries of the maternal role,” and “accepting parenting as a process.” The findings indicate that this experience represents a gradual and profound identity process, which can be conceptualized through a five-stage model (from the collapse of the biological motherhood myth to the consolidation of spiritual attachment). Consequently, success in this journey depends on the mother’s ability to redefine her identity from a “biological mother” to a “spiritual-chosen mother,” highlighting the need for continuous psychosocial support and a shift in policymakers’ focus toward post-adoption care.