Continuing Professional Development (CPD) for teachers is considered as an essential requirement in Education. In Thailand, the government has made an attempt to develop teachers through a scheme of CPD, which is seen as not yet reaching its intended goals. The aim of this study, therefore, is to examine the provision of CPD in Thailand and to search for practical ideas for CPD of teachers in the country. An investigation was carried out of the perceptions of public secondary school teachers and school administrators toward CPD for teachers in Chiang Mai, Thailand. The objectives were to highlight teachers' perception ofCPD, to study the needs of teachers, to explore the opportunities of CPD available for teachers, to reveal influential factors upon teachers, to investigate the problems and obstacles facing teachers, and to examine schools' problems, supports and school administrators' opinions toward CPD for teachers. The major fmdings were: 1) the teachers saw CPD as an important part of the teaching career; 2) the needs of teachers for CPD were high; 3) teachers do not have equal opportunities in CPD; 4) teachers were influenced by school administrators and education policy; 5) fmance is a major problem for teachers 'in CPD; 6) schools did not give enough support to teachers in CPD because the schools were lack of budget and planning, and school administrators viewed teacher development as an unimportant issue. Based on these findings, it is recommended that: the management system of CPD must be improved; follow,.up assessment activities should be conducted; opportunities of CPD should be widely opened to all teachers; and promotion, genuine supports, clear information and achievable incentives should be offered in order to encourage teachers to engage in continuing professional development.