We aimed to evaluate the effects of obesity treatment with behavioral therapy (BT) and cognitive behavioral therapy (CBT) interventions compared with multiple comparators and find effective techniques or combinations of techniques in BT and CBT interventions for weight loss. We systematically searched electronic databases and selected randomized controlled trials using CBT or BT intervention for obesity treatment in overweight adults or adults with obesity without psychological symptoms. Both pairwise meta-analysis and network meta-analysis were performed to comprehensively evaluate the comparative effects between interventions. We classified the techniques used in BT and CBT interventions and compared the treatment effects between techniques. Compared with no treatment as a common comparator, CBT was most effective for weight loss, followed by BT, usual care (UC), and minimal care (MC). CBT was a more effective intervention than BT, but the effect of CBT compared to BT was not remarkable in network estimates. The most used BT techniques were feedback and monitoring, and the most used CBT technique was cognitive restructuring. Our results indicated that CBT and BT are effective interventions for weight loss, and that successful weight loss requires more aggressive interventions such as BT or CBT than MC and UC.