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Bill Williams Alligator MT4 Expert Advisor

Bill Williams Alligator EA is a simple open-source expert advisor developed for MT4 platform to demonstrate a proof-of-concept robot that trades using the Bill Williams Alligator indicator. Below, you will find its brief description, the results of a backtest, a download link, and installation instructions.

One of the most popular indicators developed by Bill Williams is the Alligator. It is a pretty simple indicator that uses three moving averages with different periods and shifts.

Example of Bill Williams Alligator Indicator
Alligator Indicator

Here, we present to you can a free expert advisor for MetaTrader 4 based on the Alligator indicator. You can download and use it for free and also access its source code (.mq4 file) to build your own version of an Alligator EA.

About Expert Bill Williams Alligator MT4 Expert Advisor
About Alligator Expert Advisor


Alligator MT4 EA Input Parameters
Alligator EA Input Parameters
  • Position Size — to define the position size.
  • Use next entry to close the trade — to use a specific take-profit or to wait for the next entry signal.
  • Stop-loss in pips.
  • Take-profit in pips.
  • Slippage in pips.
  • Enable trade — to enable or disable the trading function.
  • Period of the Jaw.
  • Shift of the Jaw.
  • Period of the Teeth.
  • Shift of the Teeth.
  • Period of the Lips.
  • Shift of the Lips.

The type of moving average used for the signal line is a simple moving average.

Entry Signal

  • Buy signal when the three MA's are going up and the fast MA's are above the slow one.
  • Sell signal when the three MA are going down and the fast MA's are below the slow one.

Exit Signal

  • Fixed take-profit or stop-loss hit.
  • Close when the next opposite order is triggered.

Results on EUR/USD @ H1

Even though the backtest results on EUR/USD @ H1 timeframe show some profitability, the Alligator EA cannot be considered consistently profitable. It prospered thanks to just a few lucky trades while spending significant portion of test period in drawdown. The expert advisor is very simple — it could be improved with additional conditions. Apparently, using solely the Alligator indicator is not enough.

Backtesting Alligator EA - Report
Alligator EA Backtest result


The expert advisor can score highly profitable trades during clear and long trends.

Alligator EA Under Favorable Conditions
Established Trend Trade Example


In case of a choppy or ranging market, the EA loses money.

Alligator EA Performing Poorly in Choppy Market
Ranging Market Trades

What Is It Good For?

Even though the expert advisor shows some promise in the backtest, it wouldn't be a good idea to use this EA in a live trading account. It is very risky and can lead to long periods of drawdown when the market fails to trend clearly.

This expert advisor is free to download and you can use its .mq4 source file to develop your own EA's.

Installation instructions:

  1. Download the expert advisor .mq4 file.
  2. Open the MetaTrader 4 data folder (via File→Open Data Folder).
  3. Open the MQL4 Folder.
  4. Copy the .mq4 file to MQL4/Experts/ subfolder.
  5. Restart MetaTrader 4 or refresh the expert advisors list by right-clicking the Navigator subwindow of the platform and choosing Refresh.

Or you can read a more detailed instruction on how to perform the installation.

If you are interested in building your own expert advisor or knowing more about how to do it, check our MT4 Expert Advisor Template.

You can open a trading account with any of the MT4 Forex brokers to freely use the presented here expert advisor for MetaTrader 4.