Postoperative pain, swelling, and bleeding are the most common complications following soft tissue grafting procedures; however, detailed documentation is sparse in the literature. The aims of this prospective study were as follows: 1) to compare the frequency of complication occurrence after free soft tissue grafting (FSTG) or subepithelial connective tissue grafting (SCTG) procedures; 2) to evaluate the use of an acellular dermal matrix (ADM) as the donor tissue alternative to an FSTG or SCTG; and 3) to identify possible predictors for these complications. Seventy-five FSTG and 256 SCTG procedures were performed in 228 patients by a single operator. In five free soft tissue and 84 bilaminar graft procedures, an ADM was used instead of autogenous tissue. Variables such as the duration and location of procedures, smoking history, gender, and age were recorded. Patients were asked to fill out a questionnaire 1 week after the surgeries regarding postoperative pain, swelling, and bleeding. Data were analyzed using the chi2 test and logistic regression analysis. Odds ratios were calculated for moderate and severe adverse outcomes grouped together. The duration of surgical procedures was highly correlated with pain or swelling post-surgically (P = 0.001). Current smokers were three times more likely to experience post-surgical swelling (P = 0.01). Patients who underwent FSTG procedures were three times more likely to develop post-surgical pain (P = 0.002) or bleeding (P = 0.03) compared to those who received SCTG procedures. When an ADM was applied instead of autogenous tissue, the probability of swelling or bleeding was significantly reduced (odds ratio [OR] = 0.46, P = 0.02 and OR = 0.3, P = 0.001, respectively). Long surgical procedures and smoking may increase the severity and frequency of certain post-surgical complications after gingival augmentation procedures. FSTG procedures incur a higher likelihood for postoperative pain or bleeding than SCTG procedures, whereas the application of an ADM may significantly reduce the probability of swelling and bleeding.