Abstract: This paper presents the results of the study with the broad objective of analyzing the impacts of commercial investments on rural land access and acquisition process with reference to decentralization by devolution. The effects of commercial investments on customary rights to village lands, people‟s perception on foreign investments in their lands and impacts of transferring the village land to investors are explored. One village from each of the six wards with relatively higher land-related investment was purposely selected for the study. A total sample of 162 respondents from randomly selected households was enrolled in the study. Data were collected using a semi structured questionnaire and analyzed in Statistical Package for Social Sciences version 21. Results show that the ownership of investments in the district is 60.5% by non-village investors, 5.6% by village council on behalf of the community in the village communal land, 26.6% by individual villagers and 7.3% owned under joint venture. About 82.3% of households in Kisarawe district support their livelihoods through agriculture, 63.9% owning less than 5 acres (2ha) of land. Only in 12% of all households where women have control over land rights. Investors obtain land rights in two ways, compensation of villagers (36.5%) and through purchasing from individual household (63.5%). About 62.9% of investors own land permanently while 37.1% got temporary ownership. The effects of commercial investments on customary rights to village lands in Kisarawe district are not appealing. About 65.2% of respondents have revealed that their lives and household income have not changed, and some showed that their means of livelihood have declined as they have lost both land and income. About two-thirds (59.9%) of community members stated that their expectations towards commercial investment projects had not been fulfilled. Thus, large scale commercial investments in village lands is the opportunity for economic growth in Tanzania only if there is a balanced interest of the nation, investors and smallholder farmers. Tanzania should see to it that the economic status of her rural communities is improving by restructuring land tenure system towards safeguarding the customary land rights.