Climate change is happening and poses significant challenges to households, businesses carried against impact of climate change by smallholder farmers in semi-arid areas of Iringa District but little is known about their effectiveness in improving smallholders’ well-being. The overall objective of this study was to assess the effectiveness of adaptation strategies in a changing climate and climate variability in semi-arid areas of Iringa District. Specifically, the study examined smallholder farmers’ perceptions towards climate change, identified smallholder farmers’ adaptation strategies against impacts of climate change, explored barriers to smallholder farmers’ adaptation strategies, and examined the effectiveness of adaptation strategies as is being reflected in smallholder farmers’ well-being. The research design was cross sectional. A multistage sampling procedure was applied to select divisions, wards, villages based on their climatic conditions. A total of 240 respondents were drawn randomly from eight villages. Data were collected through household survey, key informant interviews, observation and focus group discussions methods. Meteorological data were collected from Tanzania Meteorological Agency. Quantitative data were analyzed through SPSS and qualitative data through content analysis. Instant Statistical Packages for Agro climatological data was used in analyzing the 54 years meteorological data of Nduli meteorological station in Iringa District. The findings revealed that smallholder farmers perceived climate change in terms of change in temperature, changes in rainfall, increase in drought condition and increase in malaria and crop pests and diseases. Change in The findings also show that smallholder farmers were adapting to impact of climate rainfall pattern, temperature pattern atjd occurrence of pests and diseases had significant impact on smallholder farmers’ households whose livelihood depends on rain-fed farming. and governments. Different adaptation strategies are and households. Ismani and Pawaga Divisions of Iringa District were purposively selected iii change through irrigation, crop diversification, planting early maturing maize varieties, planting drought resistant crops, changing of planting dates, and agriculture diversification and non-farm activities. Barriers to smallholder farmers’ adaptation strategies identified were unreliability of information on weather forecast, lack of access to agricultural extension services, and limited access to water for irrigation. Other barriers were lack of capital, lack of access to affordable credit institutions, lack of farm assets (plough and tractors), and cost of agricultural inputs. In addition, the results revealed that there were relationships between age, income and barriers to adaptation strategies. Existences of those barriers hindered effective implementation of adaptation strategies in the study area. The findings revealed that some of the adaptation strategies to impact of climate change such as change in planting dates, planting early maturing maize varieties, irrigation, application of fertilizer, and involving in petty business had positive influence on smallholder farmers’ well-being (p<0.05). This means that those adaptation strategies which had positive influence on smallholder farmers' well-being were effective against impact of climate change. Government and other stakeholders should facilitate adaptation by enabling farmers to overcome barriers reported in this study. The government of Tanzania and other stakeholders should also help smallholder farmers by supporting them in those adaptation strategies which proved to be effective to impact of climate change.Mwalimu Nyerere Memorial Academy management