The impact upper extremity impairments (UE) have on UE function in breast cancer survivors (BCS) is unclear. The purpose of this study was to evaluate the associations between upper extremity active range of motion (AROM), passive range of motion (PROM), and strength with self-reported function in BCS. BCS (n = 24) completed the Disabilities of Arm, Shoulder and Hand (DASH) and the Pennsylvania Shoulder Score (PSS). AROM and PROM of shoulder flexion, extension, external rotation (ER) at 0° and 90° of abduction, and internal rotation (IR) at 90° of abduction were measured using a digital inclinometer. Strength was measured using a hand-held dynamometer for scapular abduction and upward rotation, scapular depression and adduction, flexion, IR, ER, scaption, and horizontal adduction. All constructs of AROM, PROM, and strength were correlated with the DASH and PSS. DASH was moderately to highly correlated with 2 of 5 AROM, 2 of 5 PROM, and 6 of 7 shoulder strength measures. PSS was moderately to highly correlated with 2 of 5 AROM, 2 of 5 PROM, and 4 of 7 shoulder strength measures. Regression analysis showed that AROM explained 40% of the DASH scores and strength explained 20% of scores on the PSS. This study characterizes the impact that shoulder motion, flexibility, and strength losses have on shoulder function in BCS. Deficits in AROM and shoulder strength explained the greatest proportion of shoulder disability. Future clinical trials should consider incorporating AROM and strengthening techniques to improve shoulder use after breast cancer treatments.