LINQ, or Language Integrated Query, is a feature in C# and other .NET languages that allows developers to write queries directly in their code. It provides a consistent way to access and manipulate data from various sources, such as databases, XML documents, and in-memory collections, using a syntax similar to SQL. With LINQ, developers can filter, sort, and group data easily, making code more readable and maintainable. It supports both query syntax and method syntax, giving flexibility in how queries are expressed. Overall, LINQ simplifies data handling and enhances productivity in software development.