明信片学 （英文：Deltiology ，源于希腊文δελτίον, deltion, diminutive of δέλτος, deltos, 「书写板，信件」-λογία, -logia）是一门研究明信片搜集的学问。与集邮（philately）的差别在于明信片因为不像邮票一样集中出产，也没有完整的规范，所以明信片学常在辨认片子的产地与年代。因此，有些搜藏者会选定特定艺术家或出版者的明信片来搜集，或是专门搜集某个年代或地点的片子。

Deltiology (from Greek δελτίον, deltion, diminutive of δέλτος, deltos, "writing tablet, letter"; and -λογία, -logia) is the study and collection of postcards. Professor Randall Rhoades of Ashland, Ohio, coined a word in 1945 that became the accepted description of the study of picture postcards. It initially took about 20 years for the name to appear in a dictionary. Compared to philately, the identification of a postcard's place and time of production can often be an impossible task because postcards, unlike stamps, are produced in a decentralised, unregulated manner. For this reason, some collectors choose to limit their acquisitions to cards by specific artists and publishers, or by time and location.