diff --git a/internal/user/service/service.go b/internal/user/service/service.go
new file mode 100644
index 0000000..22bed69
--- /dev/null
+++ b/internal/user/service/service.go
@@ -0,0 +1,113 @@
+package service
+
+import (
+	"context"
+	"errors"
+	"log/slog"
+
+	"gitea.michaelthomson.dev/mthomson/habits/internal/user/repository"
+	"github.com/gofrs/uuid/v5"
+)
+
+var (
+	ErrNotFound error = errors.New("user cannot be found")
+)
+
+type User struct {
+	Id             uuid.UUID
+	Email          string
+	HashedPassword string
+}
+
+func NewUser(id uuid.UUID, email string, hashedPassword string) User {
+	return User{Id: id, Email: email, HashedPassword: hashedPassword}
+}
+
+func UserFromUserRow(userRow repository.UserRow) User {
+	return User{Id: userRow.Id, Email: userRow.Email, HashedPassword: userRow.HashedPassword}
+}
+
+func UserRowFromUser(user User) repository.UserRow {
+	return repository.UserRow{Id: user.Id, Email: user.Email, HashedPassword: user.HashedPassword}
+}
+
+func (t User) Equal(user User) bool {
+	return t.Id == user.Id && t.Email == user.Email && t.HashedPassword == user.HashedPassword
+}
+
+type UserRepository interface {
+	Create(ctx context.Context, user repository.UserRow) (repository.UserRow, error)
+	GetById(ctx context.Context, id uuid.UUID) (repository.UserRow, error)
+	Update(ctx context.Context, user repository.UserRow) error
+	Delete(ctx context.Context, id uuid.UUID) error
+}
+
+type UserService struct {
+	logger *slog.Logger
+	repo   UserRepository
+}
+
+func NewUserService(logger *slog.Logger, userRepo UserRepository) *UserService {
+	return &UserService{
+		logger: logger,
+		repo:   userRepo,
+	}
+}
+
+func (s *UserService) GetUser(ctx context.Context, id uuid.UUID) (User, error) {
+	user, err := s.repo.GetById(ctx, id)
+
+	if err != nil {
+		if err == repository.ErrNotFound {
+			return User{}, ErrNotFound
+		}
+
+		s.logger.ErrorContext(ctx, err.Error())
+		return User{}, err
+	}
+
+	return UserFromUserRow(user), err
+}
+
+func (s *UserService) CreateUser(ctx context.Context, user User) (User, error) {
+	userRow := UserRowFromUser(user)
+
+	newUserRow, err := s.repo.Create(ctx, userRow)
+
+	if err != nil {
+		s.logger.ErrorContext(ctx, err.Error())
+		return User{}, err
+	}
+
+	return UserFromUserRow(newUserRow), err
+}
+
+func (s *UserService) DeleteUser(ctx context.Context, id uuid.UUID) error {
+	err := s.repo.Delete(ctx, id)
+
+	if err == repository.ErrNotFound {
+		return ErrNotFound
+	}
+
+	if err != nil {
+		s.logger.ErrorContext(ctx, err.Error())
+	}
+
+	return err
+}
+
+func (s *UserService) UpdateUser(ctx context.Context, user User) error {
+	userRow := UserRowFromUser(user)
+
+	err := s.repo.Update(ctx, userRow)
+
+	if err == repository.ErrNotFound {
+		return ErrNotFound
+	}
+
+	if err != nil {
+		s.logger.ErrorContext(ctx, err.Error())
+	}
+
+	return err
+}
diff --git a/internal/user/service/service_test.go b/internal/user/service/service_test.go
new file mode 100644
index 0000000..4e5ccbc
--- /dev/null
+++ b/internal/user/service/service_test.go
@@ -0,0 +1,155 @@
+package service_test
+
+import (
+	"context"
+	"log/slog"
+	"testing"
+
+	"gitea.michaelthomson.dev/mthomson/habits/internal/test"
+	"gitea.michaelthomson.dev/mthomson/habits/internal/user/repository"
+	"gitea.michaelthomson.dev/mthomson/habits/internal/user/service"
+	"github.com/gofrs/uuid/v5"
+)
+
+func TestCreateUser(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+	logger := slog.Default()
+	tdb := test.NewTestDatabase(t)
+	defer tdb.TearDown()
+	r := repository.NewUserRepository(logger, tdb.Db)
+
+	userService := service.NewUserService(logger, r)
+
+	t.Run("Create user", func(t *testing.T) {
+		uuid := NewUUID(t)
+		user := service.NewUser(uuid, "test@test.com", "supersecurehash")
+
+		_, err := userService.CreateUser(ctx, user)
+
+		AssertNoError(t, err)
+	})
+}
+
+func TestGetUser(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+	logger := slog.Default()
+	tdb := test.NewTestDatabase(t)
+	defer tdb.TearDown()
+	r := repository.NewUserRepository(logger, tdb.Db)
+	uuid := NewUUID(t)
+
+	row := repository.UserRow{Id: uuid, Email: "test@test.com", HashedPassword: "supersecurehash"}
+	_, err := r.Create(ctx, row)
+	AssertNoError(t, err);
+
+	userService := service.NewUserService(logger, r)
+
+	t.Run("Get exisiting user", func(t *testing.T) {
+		_, err := userService.GetUser(ctx, uuid)
+
+		AssertNoError(t, err)
+	})
+
+	t.Run("Get non-existant user", func(t *testing.T) {
+		_, err := userService.GetUser(ctx, NewUUID(t))
+
+		AssertErrors(t, err, service.ErrNotFound)
+	})
+}
+
+func TestDeleteUser(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+	logger := slog.Default()
+	tdb := test.NewTestDatabase(t)
+	defer tdb.TearDown()
+	r := repository.NewUserRepository(logger, tdb.Db)
+	uuid := NewUUID(t)
+
+	row := repository.UserRow{Id: uuid, Email: "test@test.com", HashedPassword: "supersecurehash"}
+	_, err := r.Create(ctx, row)
+	AssertNoError(t, err);
+
+	userService := service.NewUserService(logger, r)
+
+	t.Run("Delete exisiting user", func(t *testing.T) {
+		err := userService.DeleteUser(ctx, uuid)
+
+		AssertNoError(t, err)
+	})
+
+	t.Run("Delete non-existant user", func(t *testing.T) {
+		err := userService.DeleteUser(ctx, uuid)
+
+		AssertErrors(t, err, service.ErrNotFound)
+	})
+}
+
+func TestUpdateUser(t *testing.T) {
+	t.Parallel()
+	ctx := context.Background()
+	logger := slog.Default()
+	tdb := test.NewTestDatabase(t)
+	defer tdb.TearDown()
+	r := repository.NewUserRepository(logger, tdb.Db)
+	uuid := NewUUID(t)
+
+	row := repository.UserRow{Id: uuid, Email: "test@test.com", HashedPassword: "supersecurehash"}
+	_, err := r.Create(ctx, row)
+	AssertNoError(t, err);
+
+	userService := service.NewUserService(logger, r)
+
+	t.Run("Update exisiting user", func(t *testing.T) {
+		user := service.User{uuid, "new@email.com", "supersecurehash"}
+
+		err := userService.UpdateUser(ctx, user)
+
+		AssertNoError(t, err)
+
+		newUser, err := userService.GetUser(ctx, uuid)
+
+		AssertNoError(t, err)
+
+		AssertUsers(t, newUser, user)
+	})
+
+	t.Run("Update non-existant user", func(t *testing.T) {
+		user := service.User{NewUUID(t), "new@email.com", "supersecurehash"}
+
+		err := userService.UpdateUser(ctx, user)
+
+		AssertErrors(t, err, service.ErrNotFound)
+	})
+}
+
+func AssertErrors(t testing.TB, got, want error) {
+	t.Helper()
+	if got != want {
+		t.Errorf("got error: %v, want error: %v", want, got)
+	}
+}
+
+func AssertNoError(t testing.TB, err error) {
+	t.Helper()
+	if err != nil {
+		t.Errorf("expected no error, got %v", err)
+	}
+}
+
+func AssertUsers(t testing.TB, got, want service.User) {
+	if !got.Equal(want) {
+		t.Errorf("got %+v want %+v", got, want)
+	}
+}
+
+func NewUUID(t testing.TB) uuid.UUID {
+	t.Helper()
+	uuid, err := uuid.NewV4()
+	if err != nil {
+		t.Errorf("error generation uuid: %v", err)
+	}
+	return uuid
+}