Control structures are fundamental components in programming that dictate the flow of execution within a program. They allow developers to control how and when specific blocks of code are executed based on certain conditions or iterations. In most programming languages, including Java, there are three primary types of control structures: sequence, selection, and repetition. Sequence structures execute statements in a linear order, selection structures (like if-else statements) enable decision-making, and repetition structures (such as loops) allow for the repeated execution of code blocks. Understanding these structures is essential for writing efficient and effective programs.