diff --git a/backend/app.py b/backend/app.py
index 52bf6714..1ec9e990 100644
--- a/backend/app.py
+++ b/backend/app.py
@@ -6,6 +6,7 @@
 
 from db.errors.database_errors import ActionAlreadyPerformedError, ItemNotFoundError
 from routes.errors.authentication import InvalidRoleCredentialsError, NoAccessToSubjectError
+from routes.group import group_router
 from routes.project import project_router
 from routes.student import student_router
 from routes.subject import subject_router
@@ -20,6 +21,7 @@
 app.include_router(users_router, prefix="/api")
 app.include_router(project_router, prefix="/api")
 app.include_router(subject_router, prefix="/api")
+app.include_router(group_router, prefix="/api")
 
 
 # Koppel de exception handlers
diff --git a/backend/domain/logic/group.py b/backend/domain/logic/group.py
index 76c2582c..788e95d8 100644
--- a/backend/domain/logic/group.py
+++ b/backend/domain/logic/group.py
@@ -1,4 +1,3 @@
-
 from sqlalchemy.orm import Session
 
 from db.errors.database_errors import ActionAlreadyPerformedError
@@ -51,6 +50,18 @@ def add_student_to_group(session: Session, student_id: int, group_id: int) -> No
     session.commit()
 
 
+def remove_student_from_group(session: Session, student_id: int, group_id: int) -> None:
+    student: Student = get(session, Student, ident=student_id)
+    group: Group = get(session, Group, ident=group_id)
+
+    if student not in group.students:
+        msg = f"Student with id {student_id} is not in group with id {group_id}"
+        raise ActionAlreadyPerformedError(msg)
+
+    group.students.remove(student)
+    session.commit()
+
+
 def get_students_of_group(session: Session, group_id: int) -> list[StudentDataclass]:
     group: Group = get(session, Group, ident=group_id)
     students: list[Student] = group.students
diff --git a/backend/fill_database_mock.py b/backend/fill_database_mock.py
index 880048fa..98d1b126 100644
--- a/backend/fill_database_mock.py
+++ b/backend/fill_database_mock.py
@@ -8,7 +8,7 @@
 from domain.logic.group import add_student_to_group, create_group
 from domain.logic.project import create_project
 from domain.logic.student import create_student
-from domain.logic.subject import add_teacher_to_subject, create_subject
+from domain.logic.subject import add_student_to_subject, add_teacher_to_subject, create_subject
 from domain.logic.teacher import create_teacher
 
 if __name__ == "__main__":
@@ -83,6 +83,8 @@
     add_teacher_to_subject(session, teacher2.id, algoritmen.id)
     add_teacher_to_subject(session, teacher3.id, webtech.id)
 
+    add_student_to_subject(session, student1.id, objeprog.id)
+
     # Add students to groups
     add_student_to_group(session, student1.id, groep1_objprog.id)
     add_student_to_group(session, student2.id, groep1_objprog.id)
diff --git a/backend/routes/dependencies/role_dependencies.py b/backend/routes/dependencies/role_dependencies.py
index 78ddfbd5..9de95992 100644
--- a/backend/routes/dependencies/role_dependencies.py
+++ b/backend/routes/dependencies/role_dependencies.py
@@ -3,7 +3,8 @@
 
 from db.sessions import get_session
 from domain.logic.admin import get_admin, is_user_admin
-from domain.logic.project import get_project, get_projects_of_teacher
+from domain.logic.group import get_group
+from domain.logic.project import get_project, get_projects_of_student, get_projects_of_teacher
 from domain.logic.student import get_student, is_user_student
 from domain.logic.subject import get_subjects_of_student, get_subjects_of_teacher, is_user_authorized_for_subject
 from domain.logic.teacher import get_teacher, is_user_teacher
@@ -93,3 +94,15 @@ def ensure_teacher_authorized_for_project(
     if project_id not in [project.id for project in projects_of_teacher]:
         raise NoAccessToSubjectError
     return teacher
+
+
+def ensure_student_authorized_for_group(
+    group_id: int,
+    session: Session = Depends(get_session),
+    student: StudentDataclass = Depends(get_authenticated_student),
+) -> StudentDataclass:
+    group = get_group(session, group_id)
+    projects_of_student = get_projects_of_student(session, student.id)
+    if group.project_id not in [project.id for project in projects_of_student]:
+        raise NoAccessToSubjectError
+    return student
diff --git a/backend/routes/group.py b/backend/routes/group.py
index e69de29b..22623654 100644
--- a/backend/routes/group.py
+++ b/backend/routes/group.py
@@ -0,0 +1,27 @@
+from fastapi import APIRouter, Depends
+from sqlalchemy.orm import Session
+
+from db.sessions import get_session
+from domain.logic.group import add_student_to_group, remove_student_from_group
+from domain.models.StudentDataclass import StudentDataclass
+from routes.dependencies.role_dependencies import ensure_student_authorized_for_group
+
+group_router = APIRouter()
+
+
+@group_router.post("/groups/{group_id}/join")
+def group_join(
+    group_id: int,
+    student: StudentDataclass = Depends(ensure_student_authorized_for_group),
+    session: Session = Depends(get_session),
+) -> None:
+    add_student_to_group(session, student.id, group_id)
+
+
+@group_router.post("/groups/{group_id}/leave")
+def group_leave(
+    group_id: int,
+    student: StudentDataclass = Depends(ensure_student_authorized_for_group),
+    session: Session = Depends(get_session),
+) -> None:
+    remove_student_from_group(session, student.id, group_id)