The Companions of the Prophet (Arabic: اَلصَّحَابَةُ; aṣ-ṣaḥāba meaning "the companions", from the verb صَحِبَ meaning "accompany", "keep company with", "associate with") were the disciples and followers of Muhammad who saw or met him during his lifetime, while being a Muslim and were physically in his presence. "Al-ṣaḥāba" is definite plural; the indefinite singular is masculine صَحَابِيٌّ (ṣaḥābiyy), feminine صَحَابِيَّةٌ (ṣaḥābiyyah).

Later Islamic scholars accepted their testimony of the words and deeds of Muhammad, the occasions on which the Quran was revealed and other various important matters of Islamic history and practice. The testimony of the companions, as it was passed down through trusted chains of narrators (isnads), was the basis of the developing Islamic tradition. From the traditions (hadith) of the life of Muhammad and his companions are drawn the Muslim way of life (sunnah), the code of conduct (sharia) it requires, and the jurisprudence (fiqh) by which Muslim communities should be regulated.

The two largest Islamic denominations, the Sunni and Shia, take different approaches to weighing the value of the companions' testimonies, have different hadith collections and, as a result, have different views about the ṣaḥābah.

The second generation of Muslims after the ṣaḥāba, born after the death of Muhammad, who knew at least one ṣaḥāba, are called Tābi'ūn (also "the successors"). The third generation of Muslims after the Tābi'ūn, who knew at least one Tābi, are called tābi' al-tābi'īn. The three generations make up the salaf of Islam.