In South Asia, the long-term provision of agro-ecosystem services is threatened by accelerating climate change and undesirable farming practices. Conservation farming could help ensure sustainable ecosystem services and food security. This study was conducted in nine purposively selected districts in west and northwest Bangladesh. Data on conservation farming practices were collected from 540 farmers and 63 professionals, directly or indirectly involved with conservation farming, using two interview schedules and face-to-face interviews between July and November 2019. Multiple regression modeling (OLS) and path analyses were performed to identify the contribution of selected predictors of the direct and indirect effects of using conservation farming practices. Each conservation farming practice, including the system of rice intensification under permanent raised-beds, crop residue incorporation, and cover crops, affected components of farmers’ food security. These conservation practices had moderately positive effects on agro-ecosystem services and food security for 82.2% of farmers studied. The effects of using conservation farming practices were significantly impacted by farmers’ educational qualifications, training experience, and their knowledge about the conservation farming practices. The food security status of farmers was significantly impacted by their annual family income and knowledge about conservation farming practices. Regulation of soil fertility and water, soil structure, soil retention, nutrient cycling, and zero-tillage were important components of agro-ecosystems that improved food security by increasing crop yield. This study showed that conservation practices have a positive influence on agro-ecosystem services and food security in Bangladesh, individually and in combination. We suggest that further support to conservation farming is an important policy option for decision-makers given the vulnerability of ecosystem services and a need to ensure food security in South Asia.