Object Oriented Programming (OOP) is an important and very commonly used approach to software implementation.
Developing an understanding of OOP is important in assisting you to develop software in a number of languages which are use this approach as the basis to developing programs in those languages.
Languages which substantially involve OOP include Java, C++, Objective C , C#, PHP (PHP5 onwards). Gaining an understanding of Object Orientation in software design will assist you in developing skills in these languages and other OOP languages.