In addition to being a vehicle of communicating individuals’ feelings and thoughts, writing as an action is also a domain of skill reflecting individuals’ emotional states. The act of writing becomes meaningful to learners when it is considered as an instrument of expressing learners’ thoughts, feelings and personal experiences, and of com-municating, and when used in this way (Hidi and Boscolo, 2006). Yet, some difficulties stemming from the nature of writing make it difficult for learners to take pleasure from writing activity and to establish it as a skill for lifelong use (Yaman, 2010). Research studies have exhibited that writing is a complex internal process and that it causes individuals to relax emotionally (Kloss and Lisman, 2002; Smyth, 1998; Sloan et al., 2009). On examining the components of writing – which is an internal and complex process - we find that long term active memory, cogni-tive processes, and motivation come into prominence (Sharples, 1998); and those components make the writing process individual and cause the emergence of self-efficacy perception. Unless methods for raising the motivation are available to perform a writing activity, it is impossible for writing individuals to make considerable progress and development (Ackerman, 2006). Hidi and Boscolo (2006) list the factors influencing the motivation to write as such: (1) having a desire to write, (2) having sufficient knowledge of the topic, (3) an uncomplicated topic for writing, (4) giving instant feedback for the writing, and (5) being able make constant efforts during writing Moti-vation is a broad concept containing wishes, desires, needs, impulses and interests (Cuceloglu, 2004). It is a factor which has become an important element in learning the native language and a foreign language (Vaezi, 2008) for the last thirty years, which represents one of the most attractive and most complicated variables used in explaining the individual differences in language learning (MacIntyre et al., 2001), and which is necessary for successful language acquisition (Dornyei, 2001a). Through years, students’ performances dramatically decreased despite the curricula’s expectations of the students, and several studies were conducted in relation to the issue so as to raise learners’ in-class study motivations (Ackerman, 2006). The actualisation of the writing activity depends on stu-dents’ interest in the activity, their willingness and needs. On reviewing the relevant literature, it was found that motivation for reading, which was a skill directly related with writing, was addressed by researchers and that the scale for reading motivation was developed (Wigfield and Guthrie, 1995). Research has shown that students with high motivation to read devote time to reading and that they transform reading into a habit (Gambrell, 2011). Various scales on writing anxiety were developed so as to determine the anxiexties about writing in the native language (Petzel and Wenzel, 1993) and an in foreign language (Cheng, 2004). Besides, a self-efficacy scale for writing was developed (Sengül, 2013) in relation to writing in the native language No measurement tools proved to be valid and reliable were encountered in Turkey to determine secondary school students’ levels of motivation for writing in the native language. This study aims at developing a valid and reliable scale so as to determine secondary school students’ levels of motivation to write in their native language.This research was conducted with 493 students attending the primary education schools in Istanbul. Since the selection of the participants was made on the basis of willingness, the method of purposive sampling was employed. 55.2% (272) of the participants were male while 44.8% (221) of them were female. 24.9% (123) of the students were the fifth graders whereas 31.8% (157) were the sixth graders, 23.9% (118) were the seventh graders, and 19.3% (95) were the eighth graders. Prior to the scale development work, literature was reviewed, and the scales used in similar studies were examined. In addition to that, students were asked to write a composition about writing activities in Turkish classes. Thus, a content analysis was performed for the students’ compositions and the research studies found in literature. Special care was taken to include as many trial items as possible in order to uncover the writing motivation present in primary school students; and consequently, a pool of 60 items was formed. The items were then analysed by 5 experts (measurement and evaluation experts, experts on teaching Turkish, and Turkish teachers) who had been doing their post-doctorate research. Following the modifications based on expert opinions, a form of 53 items was prepared. The construct validity was analysed for the validity study of the writing motivation scale (WMS). In order to prove the construct validity, factor analysis was performed for the data so as to find whether the scale was one dimensional or multidimensional, and if it was multidimensional, to see on what dimensions the items cluste-red. Confirmatory factor analysis was done in order to evaluate the extent to which the factors composed of a number of variables fitted the real data. So as to find whether or not the items were valid, item analysis was performed. The corrected item-total correlations were examined in relation to the evidence for the reliability of the scale, internal consistency coefficient, and item analysis. And for the analyses of the data obtained from the validity and reliability studies of the scale, the SPSS 20.0 and LISREL 8.54 programmes were used.This research aimed to develop a tool of measurement in order to determine secondary school students’ motivation for writing. The scale was composed of 4 sub-scales; namely, self-efficacy, affective state, social acceptance, and physical state. It was found in consequence of literature review that the research studies performed in relation to writing motivation focussed on such issues as purpose in writing, the need felt for writing, the value attached to writing, interest in writing (Hidi and Boscolo, 2007), belief in self-efficacy, target tendencies, interests, and results obtained (Troia et al., 2012). Besides, by taking families and writing experiences in the school setting into consideration among the factors influencing learners’ writing motivation, Nolen (2007) lay emphasis on social contexts. The first dimension in this current research was “self-efficacy”. Bandura (1986: 361) defines the concept of self-efficacy as “individu-als’ judgement of themselves in relation to the capacity to organise and successfully perform the activities neces-sary for displaying a certain level of performance”. In writing skills, a directly proportional relation exists between high motivation and self-efficacy, moreover, high motivation also paves the way for the increase of the author’s perception of self-efficacy (Bruning and Horn 2000; Pajares, 2003). The second dimension mentioned in this study was “social acceptance”. Walker and Symons (1997) consider the leading theories on human motivation as a whole and summarise the general properties of the theories in five main points. According to one of those five points, when people are approved / accepted by others, their motivation reaches the maximum level. Another dimension in this study was the “physical state”. In addition to their influence in visual-motor skills and in assuring the hand-eye coordination in the writing process, physical factors are also important in affecting the cognitive and the social development. Puberty was the period on which this research was focussed. In this period, the development of the muscles enabling writing is at a more advanced level than the one in the primary school period and it comes very close to that of mature people’s. The number of studies addressing this dimension of writing is very small in Turkey. The research studies conducted by Temur (2011), Temur et al. (2012) - which deals with such physical factors as holding the pencil, the position of the paper, the posture in sitting, and applying pressure on the paper- are remarkable in this respect. The final dimension dealt with in this research was the dimension of “affective state”. Students’ emotional status in the writing process is also important in the development of the writing skill. “Individuals’ affective side involves emotions, preferences, sensations, beliefs, expectations, attitudes, apprecia-tion, values, morals, ethics, etc. Learning the affective properties is important for individuals. This can be consi-dered from two perspectives: First, teaching purely affective properties, and second, the instrumental use of the learnt affective properties in teaching or learning the cognitive and the psychomotor behaviours. For instance, if an individual has negative attitudes towards mathematics, it becomes difficult for one to teach that person mathe-matics” (Tekindal, 2009: 1). In consequence, it may be said that the self-efficacy dimension as well as the affective state which contains interests and the concepts of value, and the social dimension have similarities to the dimen-sions addressed in other research studies. On the other hand, the dimension of physical state was not encountered in other research studies. This is an important dimension in that it is not included in other research studies.