Designing and implementing technology-based professional development of mathematics teachers is the key to fundamental, wide-ranging educational reforms. This development should be based on some suitable educational technology standards. In order to understand the extent to which the integration of technology in day-to-day teaching/learning has taken place in terms of such standards, we need to search for critical variables influencing their attainment. By adopting the ISTE Technology Foundation Standards for Students, this study used a sample of 134 mathematics teachers from Finland, Serbia and Slovakia---three countries at considerably different levels of technological development---to examine the subjects' interest to achieve these standards in relation to their computer attitudes and the received professional support concerning the standards. For these students, who studied at institutions that did not offer any explicit instruction on the utilized or other ET standards, three important findings were obtained. First, the interest was higher than the support: while on average the interest was medium, the support was rather small. Second, both the interest and the support for the Finnish subjects were lower than that for the Serbian and Slovak subjects. Third, the interest was primarily influenced by computer attitude. Implications for professional development of mathematics teachers and further research are included.