Purpose Postoperative functional outcomes such as speech and swallowing are affected by volume of tongue resected and reconstruction method in oral tongue cancer. The aim of this study is to evaluate postoperative function and determine the adequate reconstruction method after oral tongue cancer surgery. Material and Methods We studied 42 patients with oral tongue cancer who underwent glossectomy with primary closure or secondary intention (20 patients) and free flap reconstruction (22 patients). We compared the postoperative function depending on the volume of tongue resected and reconstruction method using six methods including tongue movement test (0–16 points), alternate articulation test (0–16 points), articulation screening test (0–6 points), simplified speech test (0–6 points), swallowing function using Functional Outcome of Swallowing Scale (0–5 points) and quality of life using EORTC QLQ–C30 and HN35 (65–266 points). Results The patients included 26 male (61.9%) and 16 female (38.1%), and mean age was 54.5 years. Of all patients, postoperative functional outcomes had inverse correlation with the volume of tongue resected. Of 22 patients who underwent partial glossectomy, patients with primary closure or secondary intention had better function in tongue movement test, articulation screening test, and simplified speech test than patients with free flap reconstruction (p = 0.04, 0.01, Conclusions Primary closure or secondary intention is appropriate reconstructive methods after partial glossectomy. However, free flap reconstruction is recommended after hemiglossectomy.