The aim of this theoretical paper is to discuss the researches implemented in government bond and other financial markets, and to identify the most important global factors, influencing government bond market comovements. Even though, there exist various groups of factors, influencing government bond markets, this research is concentrated in the existence of global factors. If the influence of these factors is significant, investors cannot hedge from this influence by diversifying. The research in this paper is implemented by using the analysis, synthesis and systemization of the researches and other scientific literature. This research uses a novel approach by excluding and the most common global factors, influencing government bond market comovements and discussing the measures to assess the influence of these factors on the comovements. The research resulted in identification of 5 global factors, most commonly disclosed by other researchers as influencing government bond market comovements: global risk aversion, global market portfolio, money market uncertainty, commodity market uncertainty and economic policy uncertainty, with the most important factor being global risk aversion. The existence of these factors reduces the benefits from international diversification: if the markets are strongly influence by the same global factors, the deterioration of these factors will influence the investment portfolio in the same way.