Background <p>Nutrition knowledge is crucial for a healthy pregnancy and lactation period. Misleading information about healthy nutrition can lead to health problems. Therefore, it is important to obtain information about healthy nutrition from the right sources and increase awareness of healthy nutrition, especially during these periods. This study aims to explore the relationships among nutritional knowledge level, body perception, and emotional eating among pregnant and lactating women.</p> Methods <p>A total of 200 pregnant and lactating women (100 participants each) were included. A questionnaire was created by researchers, and it consists of 5 sections covering demographic data, the Nutrition Knowledge Level Determination Scale for Adults (NKLSA), false facts about nutrition during pregnancy and lactation (FFNPL), the Photographic Figure Rating Scale (PFRS), and the Emotional Eating Questionnaire (EEQ). All the data were collected face to face from a single-center gynecology department.</p> Results <p>Pregnant and lactating women had similar nutritional knowledge levels (<i>p</i> &gt; 0.05). Basic nutritional knowledge was associated with emotional eating and FFNPL. The majority of pregnant and lactating women had moderate knowledge about basic nutrition and low emotional eating, which was particularly significant for lactating women (pregnancy <i>r</i> = 0.288 <i>p</i> &gt; 0.05, lactation <i>r</i> = 0.130 <i>p</i> &lt; 0.05).</p> Conclusion <p>The study findings suggest that pregnant and lactating women experience emotional eating and distorted body perception, which are linked to their nutritional knowledge levels. To improve nutritional knowledge among pregnant and lactating women, public health strategies, such as healthy nutrition educational programs should be planned.</p> Trial registration <p>There is no need for trial registration.</p>