Private tutoring is a widespread phenomenon in many developing countries, including Vietnam. Using the Vietnam Living Standards Surveys 1997-1998 and 1992-1993 for analysis, this paper finds evidence that private tutoring in Vietnam is a necessity in the household budget for both primary students and lower secondary students, and the trend to attend private tutoring is stronger at higher education levels. There is no evidence of gender discrimination in expenditure on private tutoring. Ethnic minority students spend less on private tutoring at the primary level but not at the lower secondary level, as do students living in rural areas. However, spending on private tutoring would fall significantly if the qualifications of primary school teachers are increased. Private tutoring is found to have significant impact on a student's academic performance, but the influence is larger for lower secondary students. This paper contributes to the available estimation techniques by extending the simultaneous Tobit model of Amemiya [(1974). Multivariate regression and simultaneous equation models when the dependent variables are truncated normal. "Econometrica, 42"(6), 999-1012] to a joint Tobit-ordered probit econometric model to address the possible endogeneity of household spending on private tutoring.