Code efficiency refers to how effectively a computer program uses resources, such as time and memory, to perform its tasks. Efficient code runs faster and consumes less memory, which is crucial for improving performance, especially in large applications or systems with limited resources. Improving code efficiency can involve optimizing algorithms, reducing redundancy, and using data structures that best fit the problem. Tools and techniques, such as profiling and benchmarking, help developers identify bottlenecks and areas for improvement, ultimately leading to more responsive and scalable software solutions.