Short answer
Yes. Smiling is a sunnah of the Prophet ﷺ and an act of charity. He said your smile in your brother's face is sadaqah, and his Companions described him as smiling more than anyone. His laugh was mostly a smile, and he warned that too much laughter deadens the heart.
Smiling at people is mustahabb (recommended) and rewarded as sadaqah. Loud, excessive laughter is disliked.
The four schools agree on this.
Explanation
The Prophet ﷺ said: your smiling in the face of your brother is charity for you. In Islam a smile is not only good manners. It is a deed written in your record, open to rich and poor alike.
His Companions remembered his smile. Jarir ibn Abdullah said that from the day he accepted Islam, the Prophet ﷺ never refused to see him and never looked at him without smiling. Aisha said she never saw him laugh so fully that the back of his mouth showed; he would only smile. So the sunnah is a warm, frequent smile, with laughter kept moderate.
Balance matters. The Prophet ﷺ advised: do not laugh too much, for much laughter deadens the heart. This is not a ban on joy, jokes or fun. He joked with his family and Companions, always truthfully. It is a warning against a life that is all entertainment and no seriousness.
Ways to live this sunnah:
- smile when you greet people with salam, at home first;
- smile at the cashier, the bus driver and the new person at the mosque;
- smile at your parents and children, who often get our tired faces;
- keep jokes truthful and kind (see are white lies haram);
- a woman smiling at non-mahram men in a flirtatious way is a different matter; ordinary politeness is fine.
The four schools agree that smiling is a recommended sunnah. More daily sunnahs in Sunnahs of daily life.
The evidence
Jami' at-Tirmidhi 1956
Grading to be checked... تبسمك في وجه أخيك لك صدقة ...
"Your smile in the face of your brother is charity for you."
Smiling is rewarded as sadaqah.
Sahih al-Bukhari 3035
Sahih... ولا رآني إلا تبسم في وجهي ...
"He never saw me except that he smiled in my face."
Smiling at people was his constant habit.
Sahih al-Bukhari 6092
Sahih... إنما كان يتبسم ...
"He would only smile."
His laughter was mostly a smile.
Sunan Ibn Majah 4193
Grading to be checked... لا تكثروا الضحك فإن كثرة الضحك تميت القلب ...
"Do not laugh too much, for much laughter deadens the heart."
Laughter should be moderate.
Where the ruling is recorded
- al-Shama'il al-Muhammadiyya (al-Tirmidhi), Chapter on the laughter of the Messenger of Allah ﷺ. Gathers the reports that his laughter was mostly smiling.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.