Attached to a verb stem to indicate two actions happening at the same time: 'while doing ~'.
音楽を聞きながら勉強するのが好きだ。
I like to study while listening to music.
歩きながら電話で話すのは危ない。
Talking on the phone while walking is dangerous.
料理を作りながら子どもの宿題を見ていた。
I was checking my child's homework while cooking.
聞きながらメモを取る習慣をつけた。
I got into the habit of taking notes while listening.
Used concessively to mean 'although' or 'despite' (often appears as 'ながらも' in formal expressions).
若いながらも彼は非常に落ち着いている。
Although young, he is very composed.
結果は振るわなかったながら、努力は認められる。
Although the results weren't good, the effort can be acknowledged.
素人ながら才能を感じさせる作品だった。
Although an amateur, the work showed real talent.
An older/formal usage meaning 'both' or 'both of them' (somewhat literary or archaic).
二つながらご査収ください。
Please accept both items.
Used in phrases like '昔ながら' or '涙ながらに' to indicate something remaining as before or being in a certain state (e.g., 'as always', 'in tears').
この店は昔ながらの味を守っている。
This shop preserves its traditional taste.
彼女は涙ながらに別れを告げた。
She said goodbye with tears.
Used as a prefix element to form words that describe doing something concurrently (e.g., 'ながら族' — people who do several things at once).
最近、ながら族と呼ばれる人が増えている。
Recently, the number of people called 'nagara-zoku' (those who multitask) has been increasing.
テレビを見ながら食事をするのは、日本ではよくある習慣だが、マナーとしては好ましくない場合もある。
Eating while watching TV is common in Japan, but sometimes considered poor manners.