Alternative weed management strategies are needed to expand the capability of weed control as weed pressures continue to limit optimum yield, and as the use of synthetic chemical herbicides for weed control becomes more restricted. Biological control of weeds is based on the premise that biotic factors influence the distribution, abundance, and competitive abilities of plant species. Biological control is one alternative means of suppressing weed growth and establishment. More than 100 microorganisms have been identified as having the potential for weed biocontrol. There are, however, a number of problems with using these agents that must be solved, including limited host spectrum, lack of consistency across environments, and slow or inadequate weed suppression. It has been shown that soil microorganisms are capable of suppressing weeds in the field. It is imperative to develop an understanding of these soil microbes and their ecology so that they may be used to benefit agriculture, especially for weed management. Further study is required so that they may be produced efficiently and used effectively in weed management strategies.