Laser transmission joint between biocompatible, dissimilar materials have the potential for application in biomedical and their encapsulation process. This paper is devoted to laser transmission joint between 0.1mm thick PET films and 0.1mm thick Titanium using near-infrared diode lasers. Response surface methodology (RSM) is used to develop mathematical models between the joining process parameters. The developed mathematical models are tested for adequacy using analysis-of-variance (ANOVA) method. In addition, the main effect of each parameter and the interaction effects with other process parameters are analyzed. Finally, the experimental results agree with those predicted indicate that the developed mathematical models can predict the responses adequately.