Background In 2015, the median duration of exclusive breastfeeding was 2.2 months in Armenia, and only 15% of 4–5-month-old children were exclusively breastfed, indicating an issue with breastfeeding knowledge and practices. Research aim To identify the main barriers to optimal breastfeeding practices in Armenia. Methods We used qualitative research methods via focus group discussions and in-depth interviews with four groups of providers from different levels of care, and mothers of young children, from Yerevan city and two provinces, Lori and Shirak. Overall, eight in-depth interviews and 13 focus group discussions were conducted with a total of 99 participants. Qualitative content analysis was applied, with elements of both inductive and deductive approaches. Results We identified two main categories of barriers to optimal breastfeeding—systemic barriers and knowledge deficiencies. The main themes within systemic barriers were lack of skilled breastfeeding support services and low motivation of providers—mainly related to inadequate recognition of their role in breastfeeding counseling and low remuneration. The main knowledge-related barriers were insufficient counseling of mothers, lack of reliable information sources about infant feeding, and misconceptions among both mothers and providers. Conclusion Optimal breastfeeding is crucial for the best start to an infant’s life; however, there were a number of barriers to optimal breastfeeding practices in Armenia. Our findings and recommendations could help policymakers apply effective strategies for improving breastfeeding rates in Armenia. Considering the similar historical backgrounds of the post-Soviet countries, our findings could also be applicable to other Commonwealth of Independent States countries.