Purpose <p>To determine whether body awareness and upper extremity functionality are affected in patients with or without lymphedema development after breast cancer surgery (BCS) in comparison with individuals without a history of cancer.</p> Methods <p>The study included a total of 102 individuals, including 34 who developed lymphedema after BCS (mean age: 43.88 ± 12.13&#xa0;years), 34 who did not develop lymphedema after BCS (age: 44.67 ± 11.20&#xa0;years), and 34 without a history of any cancer surgery (age: 45.41 ± 12.13&#xa0;years). The participants’ demographic data were recorded. Body awareness was evaluated using the Body Awareness Questionnaire, and upper extremity functionality was evaluated using the Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire.</p> Results <p>The demographic data of the groups were similar (<i>p</i> &gt; <i>0.05</i>). While there were differences between the BCS groups in terms of operative time (<i>p</i> &lt; <i>0.001</i>) and operated breast (<i>p</i> = <i>0.001</i>), the number of lymph nodes dissected and the type of surgery performed were homogeneously distributed (<i>p</i> &gt; <i>0.05</i>). Body awareness and upper extremity functionality were significantly lower in the lymphedema group than in the BCS group without lymphedema and the control group (<i>p</i> = <i>0.021</i> and <i>p</i> &lt; <i>0.001</i>, respectively).</p> Conclusion <p>The development of upper extremity lymphedema after BCS adversely affects both body awareness and upper extremity functionality.</p>