The nature of land tenure system that exercised in a certain country, may have positive/ negative implication on the security of communal land, namely, that of forest and women’s land right. This situation is very intense and an important issues in the developing country like Ethiopia, at which livelihood largely agriculture. The rationale of this investigation is an assessment on customary tenure system and its implication to women’s land right in and security of communal forest land, Belojiganfoy woreda of Benishangul Gumuz Regional State. The required data for the study is generated both from primary and secondary sources. Hence the instrument used are key informant interview (from 19 respondents), focus group discussion and questionnaire from a house hold survey of 161 heads of households, review of related document and personal observation. The findings of this study confirmed that the institution of customary tenure and its rules are presently dissociated and lack recognition. However, its long year negative implication in undermining women’s land right still dominate peoples mentality and constructed as a societal traditions. Because of this reason women’s have no equal position in terms of ownership, access and the right to convey their farm land, as of their men counter parts. Again, the case of communal forest is at a risk. Because, every one use them without limit due to dissociation of the power of customary tenure, plus the absence of strong statutory legislation in the area. At extreme case, forest land and other reserved sites are massively converted to agricultural land both by investors and farmers. Due to this reason, the region and the woreda government attempt to formalize the land tenure system, by launching a gender sensitive land tenure law and with the formal delineation of forest land for protection. However, its smooth implementation are became tedious task, due to the complexity land holding issue emanating from overlapping personal and institutional interest.