Merton's law on unintended consequences (1936) warns against the undesirable and unanticipated outcomes of every action and policy. More recent research (Zhao, 2017) in the field of education, in relation to Merton, claims that these consequences are usually treated as inconvenient side effect of a policy, but are, in fact, planned by policy-makers or other stakeholders to benefit them. It is therefore more appropriate to call them '(un)intended consequences', which are not written into the policy but are a result of how the policy translates into practice. This paper, in relation to the above approaches, aims at revealing (un)intended consequences and hidden agendas of the educational reform conducted by the Polish government in 2016, with a special focus on their impact on ECEC. (Un)intended consequences are investigated here in four dimensions, including ECEC: organisational changes, curriculum, management and educators. The paper is based on the review of literature and on the author's qualitative and quantitative research among parents, teachers and representatives of local authorities, carried out in the 2018/2019 school year.