The purposes of the present study were: (1) to examine the relationships among mathematics, achievement, self-concept, achievement motivation and attribution of success and failure, (2)  to compare pupils' attribution of success and failure who were different in  self- concept, achievement motivation, sex,  social class and grade level, 
and find the best  predicters of pupils' mathematics achievement. 
                In this study, the sample consisted of 275  Prathomsuksa 5 pupils (135 boys, 140  girls) and 275  Matayomsuksa 2 pupils (147 boys, 128 girls) in Nakornpathom  province in the academic year 1987.  These pupils 
were asked to respond to four questionaires and one achievement test. These questionaires were designed to assess pupils background  characteristics, self-concept, achievement motivation attribution of success and failure. The Prathomsuksa 4 mathematics achievement test was design to measure  mathematics achievement of Prathomsuksa 5 pupils,  and 
Matayomsuksa 1 mathematics achievement test was for Matayomsuksa 2 pupils. A pupil could attributed his (or her) success to ability, effort, good luck or  task easiness, and attributed his (or her) failure to lack of abilily, lack of effort, 
bad luck, or task defficulty. 
           The analysis of the data was done by means of the computer using the statistical package SPSSX . The staistics used were the pearson productmoment corelation, the Holelling-T2 , and the multiple corelation, 
                The research findings are as fallows: 
                1.  The positive relationship was found between pupils' self-concept and the attribution of success to abililty and effort. On the contrary, the negative relationships were found between pupils' self-concept and the  attribution 
of success to good luck, pupils' self-concept and the attribution of failure to lack of ability, bad luck, and defficulty 
of task for both grade level, However, the positive relationship was found between self-concept and the attribution of success to easy of task, only for the Matayomsuksa 2 pupils. 
                2.  Achievement motivation was positively related to the attiebution of success to  ability and  effort  for 
both grade levels. On the other hand, achievement motivation was negatively related to the attribution of success to good luck, attribution of failure to lack of ability, bad luck and difficulty of task for both grade levels. However, the achievement  motivation is  positively related to  the attribution of success to easiness of task, attribution of 
failure to lack of effort, for Matayomsuska 2 pupils only. 
                3.  For both grade level the positive relationship was found between mathematics  achievement and the 
attribution of success to ability and effort, but the negative relation was found between mattematics achievement and the attribution of failure to bad luck. Only for  Prathomsukas  5 pupils, the positive relationship was found between 
mathematics achievement and the attribution of failure to lack of effort. The mathematics achievement was found to be negtively related to the attribution of success to good luck, the attribution of failure to lack of ability, bad luck and difficulty of task, for Matayomsuksa 2 pupils only. 
                4.  Pupils with high level of self-concept attributed success to ability and effort  greater than those with 
low level of self-concept for both grade levels pupils. Those who had high level 
of self-concept attributed failure to lack of ability less than those who had low level of self-concept for both grade levels. For pupils who had high level of self-concept 
attributed failure to bad luck lese than who had low level of self-concept for Matayomsuksa 2 pupils only. 
                5.  Prathomsuksa 5 and Matayomsuksa 2 pupils who had high level of achievement motivation, attributed success to ability and effort greater than those who had low level of achievement motivation. Prathomsuksa 5 and Matayomsuksa 2 pupils who bad high level of achievement motivation attributed failure to fad luck less than those who had low achievement  level of achieveement motivation, Matyomsuksa 2 pupils who had high level of achievement motivation, Matyomsuksa 2 pupils who hadhigh level of achievement motivation attributed failure to lack of effort greater than those who had low level of achievement motivation. 
                6.  For both grade levels the attribution of success and failure was not found to the 
different in different sex groups. 
                7.  For both grade levels the attribution of success and failure was not found to the different in defferent social class. With the exclusion of Prathomsuksa 5 pupils who come from high social class. 
                8.Prathomsuksa 5  pupils attributed success to good luck and attributed failure to bad luck greater than hose in Matayomsuka 2 pupils. However, the Prathomsuka 5 pupil 
attributed success to easiness task and attributed failure to lack of effort and task difficulty 
less than those in Malayomsuka 2 pupils. 
                9.  Mathematics achievement was predieted by self-concept, achievement motivation, attribution of success to ability, effort, good luck and easy task, attribution of failure to lack of ability, lack of effort, bad luck and task defficulty, sex and social class, it was found that   the  prediction of attribution success to ability was 3.47 % for pupils in 
Prathomsuksa 5 pupils  whereas the predietion of attribution failure to task difficulty and attribution  success to ability were 6 % for pupils in Matayomsuksa 2 pupils.