Nigeria

The Government of the Federation or of a State shall not adopt any religion as State Religion. (Sec. 10)

(1) There shall be a Court of Appeal.
(2) The Court of Appeal shall consist of –
(a) a President of the Court of Appeal; and
(b) such number of Justices of the Court of Appeal, not less than forty-nine of which not less than three shall be learned in Islamic personal law, and not less than three shall be learned in Customary law, as may be prescribed by an Act of the National Assembly. (Sec. 237)

(1) An appeal shall lie from decisions of a Sharia Court of Appeal to the Court of Appeal as of right in any civil proceedings before the Sharia Court of Appeal with respect to any question of Islamic personal law which the Sharia Court of Appeal is competent to decide.
(2) Any right of appeal to the Court of Appeal from the decisions of a Sharia Court of Appeal conferred by this section shall be –
(a) exercisable at the instance of a party thereto or, with the leave of the Sharia Court of Appeal or of the Court of Appeal, at the instance of any other person having an interest in the matter; and
(b) exercised in accordance with an Act of the National Assembly and rules of court for the time being in force regulating the powers, practice and procedure of the Court of Appeal. (Sec. 244)

(1) For the purpose of exercising any jurisdiction conferred upon it by this Constitution or any other law, the Court of Appeal shall be duly constituted if it consists of not less than three Justices of the Court of Appeal and in the case of appeals from –
(a) a Sharia Court of Appeal if it consists of not less than three Justices of the Court of Appeal learned in Islamic personal law;
… (Sec. 247)

(1) The Sharia Court of Appeal shall, in addition to such other jurisdiction as may be conferred upon it by an Act of the National Assembly, exercise such appellate and supervisory jurisdiction in civil proceedings involving questions of Islamic personal law.
(2) For the purpose of subsection (1) of this section, the Sharia Court of Appeal shall be competent to decide –
(a) any question of Islamic personal law regarding a marriage concluded in accordance with that law, including a question relating to the validity or dissolution of such a marriage or a question that depends on such a marriage and relating to family relationship or the guardianship of an infant;
(b) where all the parties to the proceeding are Muslims, any question of Islamic personal law regarding a marriage, including the validity or dissolution of that marriage, or regarding family relationship, a foundling or the guardianship of an infant;
(c) any question of Islamic personal law regarding a wakf, gift, will or succession where the endower, donor, testator or deceased person is a Muslim;
(d) any question of Islamic personal law regarding an infant, prodigal or person of unsound mind who is a Muslim or the maintenance or the guardianship of a Muslim who is physically or mentally infirm; or
(e) where all the parties to the proceedings, being Muslims, have requested the court that hears the case in the first instance to determine that case in accordance with Islamic personal law, any other question. (Sec. 262)

(1) The Sharia Court of Appeal of a State shall, in addition to such other jurisdiction as may be conferred upon it by the law of the State, exercise such appellate and supervisory jurisdiction in civil proceedings involving questions of Islamic personal Law which the court is competent to decide in accordance with the provisions of subsection (2) of this section.
(2) For the purposes of subsection (1) of this section, the sharia Court of Appeal shall be competent to decide –
(a) any question of Islamic personal Law regarding a marriage concluded in accordance with that Law, including a question relating to the validity or dissolution of such a marriage or a question that depends on such a marriage and relating to family relationship or the guardianship of an infant;
(b) where all the parties to the proceedings are muslims, any question of Islamic personal Law regarding a marriage, including the validity or dissolution of that marriage, or regarding family relationship, a founding or the guarding of an infant;
(c) any question of Islamic personal Law regarding a wakf, gift, will or succession where the endower, donor, testator or deceased person is a muslim;
(d) any question of Islamic personal Law regarding an infant, prodigal or person of unsound mind who is a muslim or the maintenance or the guardianship of a muslim who is physically or mentally infirm; or
(e) where all the parties to the proceedings, being muslims, have requested the court that hears the case in the first instance to determine that case in accordance with Islamic personal law, any other question. (Sec. 277)

(1) In exercising his powers under the foregoing provisions of this Chapter¹⁰ in respect of appointments to the offices of Justices of the Supreme court and Justices of the Court of Appeal, the President shall have regard to the need to ensure that there are among the holders of such offices persons learned in Islamic personal law and persons learned in Customary law.
(2) For the purposes of subsection (1) of this section –
(a) a person shall be deemed to be learned in Islamic personal law if he is a legal practitioner in Nigeria and has been so qualified for a period of not less than fifteen years in the case of a Justice of the Supreme Court or not less than twelve years in the case of a Justice of the Court of Appeal and has in either case obtained a recognized qualification in Islamic law from an institution acceptable to the National Judicial Council; and
… (Sec. 288)

…
61. The formation, annulment and dissolution of marriages other than marriages under Islamic law and Customary law including matrimonial causes relating thereto.
… (Second Schedule – Legislative Powers, Part I – Exclusive Legislative List)