Background Thoracotomy is associated with severe postoperative pain. Pain developing after thoracotomy causes lung infections, inability to expel secretions, and atelectasis as a result of deep breathing. Effective management of acute pain after thoracotomy may prevent these complications. A multimodal approach to analgesia is widely employed by thoracic anesthetists using a combination of regional anesthetic blockade and systemic analgesia, with both non-opioid and opioid medications and local anesthesia blockade. Nowadays, regional anesthesia techniques such as thoracic epidural paravertebral block (PVB), erector spinae plane block (ESPB), and serratus plane block are frequently used to prevent pain after thoracotomy. In this study, we compared paravertebral block with erector spinae block for pain relief after thoracotomy. Our primary aim was to determine whether there was a difference between postoperative opioid consumption and pain scores. We also compared the two regional anesthesia techniques in terms of intraoperative hemodynamic data and postoperative complications. Methodology Patients aged between 18 and 75 years with an American Society of Anesthesiology (ASA) physical status I-III and scheduled for elective thoracotomy were included in the study. Using www.randomizer.org, patients were divided into two different groups, namely, ESPB and PVB.All patients were provided with a patient-controlled analgesia device preloaded with morphine. Postoperative 24-hour morphine consumptions were recorded. Results Data from 45 patients were used in the final analyses. Morphine consumption was higher in the ESPB group than in the PVB group at 24 hours postoperatively (19.2 ± 4.26 mg and 16.2 ± 2.64 mg, respectively; p < 0.05).There was no significant difference in numerical rating scale scores both at rest and with coughing (p > 0.05). Intraoperative heart rates were similar between groups. However, mean intraoperative blood pressure was significantly lower in the PVB group at 30 minutes (p < 0.05). Nausea and vomiting were observed in two patients in the ESPB group and one patient in the PVB group. The complication of nausea and vomiting was not statistically significant between the two groups (p > 0.05). Catastrophic complications such as hematoma, pneumothorax, and local anesthetic systemic toxicity were not observed in either group. Conclusions We found that patients who underwent PVB consumed less morphine postoperatively than patients who underwent ESPB. However, we did not observe any difference in pain scores between both groups. We think that ESPB can be considered a reliable method in thoracotomy surgery due to its ease of application and the fact that the place where the block is technically performed is farther from the central structures compared to PVB.In light of the results of our study, ESPB can be used as an alternative to PVB, which has been proven as postoperative analgesia in thoracic surgery.