Gender equality within Local Government Authorities (LGAs) is an important aspect for spearheading sustainable development in any country. Gender Mainstreaming Strategies (GMSs) are set to achieve Gender equality. Despite various GMSs, gender gaps and their negative impacts to sustainable development persist in Tanzania. This can be attributed to various challenges in the course of implementing GMSs. However, in Tanzania, few studies have uncovered levels of gender equality as a result of GM in LGAs. Likewise, the data for challenges which may be impeding the implementation of various GMSs are scarce. Hence, this paper is about (i) assessing some implemented GMSs (ii) determining challenges encountered in mainstreaming gender, (iii) examining the levels of gender equality achieved in the LGAs as a result of GMSs and (iv) determining gender equality levels of men and women officials in urban and rural areas. A cross-sectional research design was employed using 358 respondents. Levels of gender equality achieved were measured by using a Composite Gender Equality Index (CGEI). The Index was adopted from the European Union Gender Equality Index (GEI) whose measure of Gender Equality (GE) ranges from 1 to 100. The Man Whitney U test was used to test the hypothesis that (i) gender equality levels are the same between male and female officials and also between Dodoma Municipality and Mpwapwa District officials. The results showed that most of GMSs were not well implemented; therefore LGAs planners should make sure that the implementation of existing GMSs is ensured according to government priorities and frameworks. Since, the overall gender equality level was found to be low (34.7% and 24.6% for male and female respectively); hence more gender mainstreaming strategies have to be implemented at the LGA level so as to spearhead sustainable development. Moreover, the equality level was generally found to be the same for both male and female, urban and rural officials, then, policy planners and LGAs gender sensitising bodies such as NGOs, media and CBOs were urged toprovide GM measures targeting both MDC and DMC equally. Since large number of men reported high level of gender equality while the overall level of gender equality was low, then it is recommended that men should be used by policy makers as agents for change towards gender equality as they occupy many decision making positions in LGAs as compared to women.