Green Marketing is among the contemporary issues in the field of Marketing. While many studies have been done in this field elsewhere, little studies have been conducted in Tanzania. Thus, this study aimed at identifying the level of green marketing adoption among agro-processing businesses in the context of Tanzania and studying the influence of business size on green marketing adoption. Data were collected from 120 micro, small and medium enterprises operating in agro-processing sector in Morogoro region. The findings show that, the level of adoption of green marketing practices is low as most businesses adopted relatively few practices. Also, it was found that, there is an association between business size and level of adoption of green marketing practices. It has to be noted that, the findings are limited to agro processing industry in Morogoro since the applicability of these findings to other industries is uncertain as data were collected in agro-processing industry.