In the below example I have created a Horizontal RecyclerView.

Here first I have added RecyclerView dependency to Grandle file.
In second step I have added a RecyclerView and Set RecyclerView  gravity (center_horizontal). Now see In MainActivity code  LinearLayoutManager's Orientation to HORIZONTAL.
You can see below example code it clearly describes How to make "horizontal RecyclerView in android".

Step(1)-I have added first RecyclerView and CardView dependency to Grandle file -
      
      

 compile 'com.android.support:recyclerview-v7:21.0.+'
       compile 'com.android.support:cardview-v7:21.0.+'

 Step(2)-activity_main.xml layout-

 <?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@+id/divider_one"
        android:layout_marginTop="15dp"
        >
        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/tv_members"

            android:text="Top Profils"
            android:textSize="17dp"
            android:textColor="#1b1a1a"
            android:textStyle="bold"
            android:layout_marginLeft="15dp"/>

        <!--  Recycler View  -->


        <android.support.v7.widget.RecyclerView
            android:layout_marginTop="30dp"
            xmlns:android="http://schemas.android.com/apk/res/android"
            android:id="@+id/recycler_view"
            android:layout_marginLeft="20dp"
            android:layout_marginRight="20dp"
            android:layout_width="fill_parent"
            android:layout_height="100dp"
            android:layout_gravity="center_horizontal"/>
    </RelativeLayout>


</LinearLayout>    

Step(3)-Created a picture_row.xml layout-

<android.support.v7.widget.CardView
    xmlns:card_view="http://schemas.android.com/apk/res-auto"
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/card_view"
    android:layout_gravity="center"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    card_view:cardUseCompatPadding="true">

    <!--   Recycler View Item Row   -->
    <LinearLayout
        android:layout_width="fill_parent"
        android:orientation="vertical"
        android:id="@+id/main"
        android:layout_height="fill_parent">


        <ImageView
            android:id="@+id/image"
            android:layout_gravity="center_horizontal"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:scaleType="centerCrop" />


    </LinearLayout>

</android.support.v7.widget.CardView>

Step(4)-Created a new class Picture_data-

public class Picture_data {


    private int image;

    public Picture_data(int image) {
        this.image = image;
    }

    public int getImage() {
        return image;
    }
}

Step(5)-Created a new class Picture_RecyclerView_Adapter -

public class Picture_RecyclerView_Adapter extends RecyclerView.Adapter<Picture_RecyclerView_Adapter.MyViewHolder> {

    private List<Picture_data>data;

    public Picture_RecyclerView_Adapter(List<Picture_data> data){
        this.data = data;
    }


    public class MyViewHolder extends RecyclerView.ViewHolder  {

        public ImageView imageView;
        private LinearLayout main;

        public MyViewHolder(final View parent) {
            super(parent);
            imageView = (ImageView) parent.findViewById(R.id.image);
            main = (LinearLayout) parent.findViewById(R.id.main);
            main.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(itemView.getContext(), "Position:" + Integer.toString(getPosition()), Toast.LENGTH_SHORT).show();

                }
            });
        }
    }


    @Override
    public Picture_RecyclerView_Adapter.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.pictures_row,parent,false);
        return new MyViewHolder(itemView);
    }
    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {

        Picture_data row = data.get(position);


        holder.imageView.setImageResource(row.getImage());

    }
    @Override
    public int getItemCount() {
        return data.size();
    }
}

Step(6)- MainActivity-
 

 public class MainActivity extends AppCompatActivity {
    private List<Picture_data>data=new ArrayList<>();
    private RecyclerView recyclerView;
    private Picture_RecyclerView_Adapter picture_recyclerView_adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        recyclerView=(RecyclerView)findViewById(R.id.recycler_view);
        setData();
         picture_recyclerView_adapter= new Picture_RecyclerView_Adapter(data);
        RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getApplicationContext(),LinearLayoutManager.HORIZONTAL,false);
        recyclerView.setLayoutManager(layoutManager);
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        recyclerView.setAdapter(picture_recyclerView_adapter);


    }

    private void setData() {
        Picture_data item = new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);
        item =new Picture_data(R.drawable.people);
        data.add(item);

    }

}