This study applied principal components analysis (PCA) and cluster analysis (CA) to assess water quality and recommend sites and water parameters for water quality monitoring at Bung Binh Thien reservoir, An Giang province, Vietnam based on 11 water samples collected in the dry season. The water variables including temperature (T), pH, electricity conductivity (EC), total dissolved solids (TDS), total suspended solids (TSS), depth (H), turbidity (NTU), dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), sulfate (SO₄^2-), chloride (Cl^-) ammonia (NH₄⁺-N), nitrate (NO₃^--N), total nitrogen (TN), orthophosphate (PO₄^3--P), total phosphorus (TP), and coliforms were used for interpretation of surface water quality and multivariate statistical analysis. The results indicated that water quality in the reservoir contaminated by suspended solid, organic matter was and fecal microbes. PCA identified five sources of water pollution accounting for 93.4% of water quality variation. CA showed that only two sampling points are needed for water monitoring in the reservoir. At each sampling point, water quality variables of temperature, pH, BOD (or COD), NO₃^--N, TP, and coliforms should be monitored and recommended by using PCA. This study suggests that multivariate statistical analysis could be useful for recommending locations and selecting water parameters for water quality monitoring