Gene therapy is an emerging field in medical and pharmaceutical sciences because of its potential in treating chronic diseases like cancer, viral infections, myocardial infarctions, and genetic disorders. Application of gene therapy is limited because of lack of suitable methods for proper introduction of genes into cells and therefore, this is an area of interest for most of the researchers. To achieve successful gene therapy, development of proper gene delivery systems could be one of the most important factors. Several nonviral and viral gene transfer methods have been developed. Even though the viral agents have a high transferring efficiency, they are difficult to handle due to their toxicity. To overcome the safety problems of the viral counterpart, several nonviral in vitro and in vivo gene delivery systems are developed. Out of these, the most promising and latest systems include polymer-based nonviral gene carriers, dendrimers, and physical means like electroporation, microinjection, etc., Shunning of possible immunogenicity and toxicity, and the feasibility of repeated administration are some of the merits of nonviral gene delivery systems over viral gene delivery. An ideal nonviral gene carrying system should possess all these merits without any compromise to its gene transferring efficiency. The viral gene delivery systems include lytic and nonlytic vectors for drug delivery. Inspite of its toxicity they are still preferred because of their long term expression, stability, and integrity. This review explores the recent developments and relevancy of the novel gene delivery systems in gene therapy.