Abraham (Avraham) ben Samuel Firkovich (Hebrew אברהם בן שמואל‎ - Avraham ben Shmuel; Karayce: Аврагъам Фиркович - Avragham Firkovich; Polish: Abraham Firkowicz; Sept. 27, 1786–June 7, 1874) was a Karaite writer and archaeologist, collector of ancient manuscripts, and a Karaite Hakham. He was born in Lutsk, Volhynia and died in Çufut Qale, Crimea. Gabriel Firkovich of Troki was his son-in-law.

Abraham Firkovich was born in 1787 into a Crimean Karaite farming family in Lutsk, then part of Poland, now Ukraine. In 1818 he was serving the local Crimean Karaite communities as a junior hazzan, or religious leader, and he went in 1822 to the city of Yevpatoria in Crimea. The Karaite community there appointed him hazzan in 1825. Together with the Karaite noble Simha Babovich, he sent memoranda to the czar, with proposals to relieve Karaites from the heavy taxes imposed on the Jewish community. In 1828 he moved to Berdichev, where he met many Hasids and learned more about their interpretations of Jewish scriptures based on the Talmud and rabbinic tradition. The encounter with Rabbinical Jews brought Firkovich into conflict with them. He published a book, Massah and Meribah which argued against the predominant Jewish halakha of the Rabbinites. In 1830 he visited Jerusalem, where he collected many Jewish manuscripts. On his return he remained for two years in Constantinople as a teacher in the Karaite community. He then went to Crimea and organized a society to publish old Karaite works, of which several appeared in Yevpatoria (Koslov) with his commentary. In 1838, he tutored the children of Sima Babovich, head of the Crimean Karaites, who a year later recommended him to Count Vorontzov and to the Historical Society of Odessa as a suitable man to send to collect material on the history of Crimean Karaites. In 1839, Firkovich began excavations in the ancient cemetery of Çufut Qale, and unearthed many old tombstones, claiming that some of them dated from the first centuries of the common era. The following two years were spent in travels through the Caucasus, where he ransacked the genizots of old Jewish communities and collected many valuable manuscripts. He travelled as far as Derbent, and returned in 1842. In later years he made other journeys of the same nature, visiting Egypt and other countries. In Odessa he became the friend of Bezalel Stern and of Simchah Pinsker. While in Vilnius, he made the acquaintance of Samuel Joseph Fuenn and other Hebrew scholars. In 1871, he visited the small Karaite community in Halych, Galicia, where he introduced several reforms. From there he went to Vienna, where he was introduced to Count Beust and also made the acquaintance of Adolph Jellinek. He returned to spend his last days in Çufut Qale, of which only a few buildings and many ruins now remain. However, Firkovich's house is still preserved at the site.

Firkovich collected a vast number of Hebrew, Arabic and Samaritan manuscripts during his many travels in his search for evidence on the traditions of his people. These included thousands of Jewish documents from throughout the Russian Empire in what became known as the First Firkovich Collection. His Second Collection contains material collected from the Near East. His visit took place about thirty years before Solomon Schechter's more famous trip to Egypt. This "Second Firkovich Collection" contains 13,700 items and is of incredible value.^{[better source needed]}

As a result of his research he became focused on the origin of the ancestors of the Crimean Karaites who he claimed had arrived in Crimea before the common era. The Karaites, therefore, could not be seen as culpable for the crucifixion of Jesus because they had settled in Crimea at such an early date. His theories persuaded the Russian imperial court that Crimean Karaites could not be accused of Jesus' crucifixion and they were excluded from the restrictive measures against Jews. Many of his findings were disputed immediately after his death, and despite their important value there is still controversy over many of the documents he collected.

The Russian National Library purchased the Second Firkovich Collection in 1876, a little more than a year after Firkovich's death.

Among the treasures in the Firkovich collection is a manuscript of the Garden of Metaphors, an aesthetic appreciation of Biblical literature written in Judeo-Arabic by one of the greatest of the Sephardi poets, Moses ibn Ezra.

Firkovich's life and works are of great importance to Karaite history and literature. His collections at the Russian National Library are important to biblical scholars and to historians, especially those of the Karaite and Samaritan communities. Controversy continues regarding his alleged discoveries and the reliability of his works.

Firkovich's chief work is his "Abne Zikkaron," containing the texts of inscriptions discovered by him (Wilna, 1872). It is preceded by a lengthy account of his travels to Daghestan, characterized by Strack as a mixture of truth and fiction. His other works are "Ḥotam Toknit," antirabbinical polemics, appended to his edition of the "Mibḥar Yesharim" by Aaron the elder (Koslov, 1835); "Ebel Kabod," on the death of his wife and of his son Jacob (Odessa, 1866); and "Bene Reshef", essays and poems, published by Peretz Smolenskin (Vienna, 1871).