1diff --git a/DOCS.md b/DOCS.md
  2index 5cbe883..0e497a6 100644
  3--- a/DOCS.md
  4+++ b/DOCS.md
  5@@ -2029,6 +2029,16 @@
  6 @returns {number} 
  7 @constructor
  8 ```
  9+
 10+### RSQ 
 11+
 12+```
 13+  Returns the square of the Pearson correlation coefficient based on the given values. 
 14+@param rangeY - An array or range of data points. 
 15+@param rangeX - An array or range of data points. 
 16+@returns {number} 
 17+@constructor
 18+```
 19 ## Text
 20 
 21 
 22diff --git a/TODO.md b/TODO.md
 23index de1297d..d26cc78 100644
 24--- a/TODO.md
 25+++ b/TODO.md
 26@@ -70,7 +70,6 @@ Many of these formulas can be written by allowing the Sheet and Parser to return
 27 * RANK
 28 * RANK.AVG
 29 * RANK.EQ
 30-* RSQ
 31 * SKEW
 32 * STEYX
 33 * T.INV
 34diff --git a/dist/Formulas/AllFormulas.js b/dist/Formulas/AllFormulas.js
 35index d50175b..a8f463a 100644
 36--- a/dist/Formulas/AllFormulas.js
 37+++ b/dist/Formulas/AllFormulas.js
 38@@ -188,6 +188,7 @@ exports.VARP = Statistical_1.VARP;
 39 exports.VARA = Statistical_1.VARA;
 40 exports.VAR = Statistical_1.VAR;
 41 exports.PERMUT = Statistical_1.PERMUT;
 42+exports.RSQ = Statistical_1.RSQ;
 43 var Text_1 = require("./Text");
 44 exports.ARABIC = Text_1.ARABIC;
 45 exports.CHAR = Text_1.CHAR;
 46diff --git a/dist/Formulas/Statistical.js b/dist/Formulas/Statistical.js
 47index b27389b..49b5474 100644
 48--- a/dist/Formulas/Statistical.js
 49+++ b/dist/Formulas/Statistical.js
 50@@ -1691,3 +1691,37 @@ var PERMUT = function (total, objects) {
 51     return _fact(total) / _fact(total - objects);
 52 };
 53 exports.PERMUT = PERMUT;
 54+/**
 55+ * Returns the square of the Pearson correlation coefficient based on the given values.
 56+ * @param rangeY - An array or range of data points.
 57+ * @param rangeX - An array or range of data points.
 58+ * @returns {number}
 59+ * @constructor
 60+ */
 61+var RSQ = function (rangeY, rangeX) {
 62+    ArgsChecker_1.ArgsChecker.checkLength(arguments, 2, "RSQ");
 63+    if (!Array.isArray(rangeY)) {
 64+        rangeY = [rangeY];
 65+    }
 66+    if (!Array.isArray(rangeX)) {
 67+        rangeX = [rangeX];
 68+    }
 69+    var dataX = Filter_1.Filter.flattenAndThrow(rangeX).filter(function (value) {
 70+        return typeof value !== "string";
 71+    }).map(function (value) {
 72+        return TypeConverter_1.TypeConverter.valueToNumber(value);
 73+    });
 74+    var dataY = Filter_1.Filter.flattenAndThrow(rangeY).filter(function (value) {
 75+        return typeof value !== "string";
 76+    }).map(function (value) {
 77+        return TypeConverter_1.TypeConverter.valueToNumber(value);
 78+    });
 79+    if (dataX.length !== dataY.length) {
 80+        throw new Errors_1.NAError("SLOPE has mismatched argument count " + dataX.length + " vs " + dataY.length + ".");
 81+    }
 82+    if (dataY.length === 1 && dataX.length === 1) {
 83+        throw new Errors_1.DivZeroError("Evaluation of function RSQ caused a divide by zero error.");
 84+    }
 85+    return Math.pow(PEARSON(dataX, dataY), 2);
 86+};
 87+exports.RSQ = RSQ;
 88diff --git a/src/Formulas/AllFormulas.ts b/src/Formulas/AllFormulas.ts
 89index a56c3ab..76c0ffb 100644
 90--- a/src/Formulas/AllFormulas.ts
 91+++ b/src/Formulas/AllFormulas.ts
 92@@ -193,7 +193,8 @@ import {
 93   VARP,
 94   VARA,
 95   VAR,
 96-  PERMUT
 97+  PERMUT,
 98+  RSQ
 99 } from "./Statistical";
100 import {
101   ARABIC,
102@@ -461,5 +462,6 @@ export {
103   VARP,
104   VARA,
105   VAR,
106-  PERMUT
107+  PERMUT,
108+  RSQ
109 }
110\ No newline at end of file
111diff --git a/src/Formulas/Statistical.ts b/src/Formulas/Statistical.ts
112index 871a693..9bf7558 100644
113--- a/src/Formulas/Statistical.ts
114+++ b/src/Formulas/Statistical.ts
115@@ -1674,6 +1674,41 @@ var PERMUT = function (total, objects) {
116 };
117 
118 
119+/**
120+ * Returns the square of the Pearson correlation coefficient based on the given values.
121+ * @param rangeY - An array or range of data points.
122+ * @param rangeX - An array or range of data points.
123+ * @returns {number}
124+ * @constructor
125+ */
126+var RSQ = function (rangeY, rangeX) {
127+  ArgsChecker.checkLength(arguments, 2, "RSQ");
128+  if (!Array.isArray(rangeY)) {
129+    rangeY = [rangeY];
130+  }
131+  if (!Array.isArray(rangeX)) {
132+    rangeX = [rangeX];
133+  }
134+  var dataX = Filter.flattenAndThrow(rangeX).filter(function (value) {
135+    return typeof value !== "string";
136+  }).map(function (value) {
137+    return TypeConverter.valueToNumber(value);
138+  });
139+  var dataY = Filter.flattenAndThrow(rangeY).filter(function (value) {
140+    return typeof value !== "string";
141+  }).map(function (value) {
142+    return TypeConverter.valueToNumber(value);
143+  });
144+  if (dataX.length !== dataY.length) {
145+    throw new NAError("SLOPE has mismatched argument count " + dataX.length + " vs " + dataY.length + ".");
146+  }
147+  if (dataY.length === 1 && dataX.length === 1) {
148+    throw new DivZeroError("Evaluation of function RSQ caused a divide by zero error.");
149+  }
150+  return Math.pow(PEARSON(dataX, dataY), 2);
151+};
152+
153+
154 export {
155   AVERAGE,
156   AVERAGEA,
157@@ -1726,5 +1761,6 @@ export {
158   VARP,
159   VARA,
160   VAR,
161-  PERMUT
162+  PERMUT,
163+  RSQ
164 }
165\ No newline at end of file
166diff --git a/tests/Formulas/StatisticalTest.ts b/tests/Formulas/StatisticalTest.ts
167index 04e2798..ea666a3 100644
168--- a/tests/Formulas/StatisticalTest.ts
169+++ b/tests/Formulas/StatisticalTest.ts
170@@ -50,7 +50,8 @@ import {
171   VARP,
172   VARA,
173   VAR,
174-  PERMUT
175+  PERMUT,
176+  RSQ
177 } from "../../src/Formulas/Statistical";
178 import * as ERRORS from "../../src/Errors";
179 import {
180@@ -1040,4 +1041,21 @@ test("PERMUT", function() {
181   catchAndAssertEquals(function() {
182     PERMUT.apply(this, [1, 2, 3]);
183   }, ERRORS.NA_ERROR);
184+});
185+
186+test("RSQ", function() {
187+  assertEquals(RSQ([10, 22, 4], [1, 3, 7]), 0.2500000000000001);
188+  assertEquals(RSQ([10, 22], [1, 3]), 1);
189+  catchAndAssertEquals(function() {
190+    RSQ([1, 2, 3], [1, 2]);
191+  }, ERRORS.NA_ERROR);
192+  catchAndAssertEquals(function() {
193+    RSQ(1, 1);
194+  }, ERRORS.DIV_ZERO_ERROR);
195+  catchAndAssertEquals(function() {
196+    RSQ.apply(this, [[1], [1], [1]]);
197+  }, ERRORS.NA_ERROR);
198+  catchAndAssertEquals(function() {
199+    RSQ.apply(this, [[1]]);
200+  }, ERRORS.NA_ERROR);
201 });
202\ No newline at end of file
203diff --git a/tests/SheetFormulaTest.ts b/tests/SheetFormulaTest.ts
204index 4f2431f..f6d8518 100644
205--- a/tests/SheetFormulaTest.ts
206+++ b/tests/SheetFormulaTest.ts
207@@ -910,6 +910,9 @@ test("Sheet PERMUT", function(){
208   assertFormulaEquals('=PERMUT(4, 2)', 12);
209 });
210 
211+test("Sheet RSQ", function(){
212+  assertFormulaEquals('=RSQ([10, 22, 4], [1, 3, 7])', 0.2500000000000001);
213+});
214 
215 test("Sheet *", function(){
216   assertFormulaEquals('= 10 * 10', 100);