A nested if statement means writing one if inside another if.

The inner condition runs only after the outer condition becomes true.

if condition1:
    if condition2:
        statements

This pattern is useful when a second check depends on the first one passing.

Nested conditions are useful when one condition depends on another condition. The inner block runs only when the outer condition is true.

Login validation and eligibility checks are common real-world examples.

Python supports multiple nested levels, so we can check more than two conditions when needed.

Deep nesting should be used carefully so the code stays readable.

If the outer if becomes false, the inner condition is never checked.