This study, which used a sample of 137,346 students from thirty three countries that participated in the TIMSS 2003 project in the eighth grade, examined the features of the individual and collective relations of three dimensions of mathematics attitude to mathematics achievement (MA), searching for the dimension mostly related to that achievement. The three dimensions of mathematics attitude were self-confidence in learning mathematics (SCLM), liking mathematics (LM) and usefulness of mathematics (UM). By utilizing psychometrically valid and reliable measures of the three dimensions, it was found that: (1) each dimension of mathematics attitude alone was positively related to MA for almost all thirty three countries; (2) SCLM was primarily related to MA for thirty one countries; (3) when the two other dimensions were held constant, SCLM was positively related to MA for thirty three countries, LM was negatively related to MA for thirty countries, whereas UM was not related to MA for twenty one countries; (4) positive collective relationships of SCLM, LM and UM to MA considerably varied from country to country. Implications for research and practice are included.