Background <p>Complete breastfeeding cessation is an important maternal–child health transition and is distinct from complementary feeding, which the World Health Organization defines as providing foods in addition to milk when milk alone is no longer adequate (generally from 6 to 23 months). Evidence on how mothers decide to stop breastfeeding and which practices they use remains limited in LMICs. This study described breastfeeding cessation timing, decision-making, practices, and support-seeking among mothers in Tehran, Iran, using a Social Ecological Model to organize influences at individual, interpersonal, healthcare/organizational, and broader contextual levels. </p> Methods <p>We conducted a cross-sectional online survey from March to August 2021 among mothers of healthy singleton children aged 6 months to &lt;4 years, recruited from 28 public health centers in Tehran. The final analytic sample included 420 mothers. Data were collected using a 42-item questionnaire with structured items and optional open-text questions; open-text responses were provided by 98–380 mothers, depending on the item. Quantitative data were summarized descriptively, and associations were examined using bivariate tests. Open-text responses were analyzed using thematic content analysis to contextualize the survey findings. Findings were organized using the Social Ecological Model across individual, interpersonal, healthcare/organizational, and broader contextual levels.</p> Results <p>Most mothers were aged 25–34 years (69.3%), reported average financial status (79.8%), and held a university degree (45.5%); children were primarily aged 42–48 months. Breastfeeding cessation was mainly mother-initiated (86.4%), and 56.2% reported complete cessation between 18 and 24 months. Traditional practices to discourage breastfeeding were common, including applying bitter or adhesive substances (41.2%) and using medicinal products without prescription (32.9%). Only 34.8% consulted healthcare providers during cessation, most often for emotional reassurance. Family advice influenced some decisions (22.3%). Mothers reported mixed experiences after cessation, including relief as well as guilt and breast discomfort, while many reported child behavioral challenges (e.g., irritability and clinginess) alongside perceived increases in independence. </p> Conclusions <p>In this Tehran sample, breastfeeding cessation was largely mother-initiated but frequently involved traditional practices and limited professional support. Findings suggest a need for clear, culturally sensitive guidance and counseling on breastfeeding cessation within routine maternal–child health services, including family engagement and practical support for gradual cessation.</p> Trial registration <p>Not applicable, as this study did not involve a health care intervention.</p>