diff --git a/UnitsNet.Tests/CustomCode/SpeedTests.cs b/UnitsNet.Tests/CustomCode/SpeedTests.cs
index 1949266c8c..862e98021a 100644
--- a/UnitsNet.Tests/CustomCode/SpeedTests.cs
+++ b/UnitsNet.Tests/CustomCode/SpeedTests.cs
@@ -47,5 +47,10 @@ protected override double MilesPerHourInOneMeterPerSecond
         {
             get { return 2.23694; }
         }
+
+        protected override double MillimetersPerSecondInOneMeterPerSecond
+        {
+            get { return 1000; }
+        }
     }
 }
\ No newline at end of file
diff --git a/UnitsNet.Tests/GeneratedCode/SpeedTestsBase.g.cs b/UnitsNet.Tests/GeneratedCode/SpeedTestsBase.g.cs
index 44105a7cfe..895bdf5b8d 100644
--- a/UnitsNet.Tests/GeneratedCode/SpeedTestsBase.g.cs
+++ b/UnitsNet.Tests/GeneratedCode/SpeedTestsBase.g.cs
@@ -41,6 +41,7 @@ public abstract partial class SpeedTestsBase
         protected abstract double KnotsInOneMeterPerSecond { get; }
         protected abstract double MetersPerSecondInOneMeterPerSecond { get; }
         protected abstract double MilesPerHourInOneMeterPerSecond { get; }
+        protected abstract double MillimetersPerSecondInOneMeterPerSecond { get; }
 
 // ReSharper disable VirtualMemberNeverOverriden.Global
         protected virtual double FeetPerSecondTolerance { get { return 1e-5; } }
@@ -48,6 +49,7 @@ public abstract partial class SpeedTestsBase
         protected virtual double KnotsTolerance { get { return 1e-5; } }
         protected virtual double MetersPerSecondTolerance { get { return 1e-5; } }
         protected virtual double MilesPerHourTolerance { get { return 1e-5; } }
+        protected virtual double MillimetersPerSecondTolerance { get { return 1e-5; } }
 // ReSharper restore VirtualMemberNeverOverriden.Global
 
         [Test]
@@ -59,6 +61,7 @@ public void MeterPerSecondToSpeedUnits()
             Assert.AreEqual(KnotsInOneMeterPerSecond, meterpersecond.Knots, KnotsTolerance);
             Assert.AreEqual(MetersPerSecondInOneMeterPerSecond, meterpersecond.MetersPerSecond, MetersPerSecondTolerance);
             Assert.AreEqual(MilesPerHourInOneMeterPerSecond, meterpersecond.MilesPerHour, MilesPerHourTolerance);
+            Assert.AreEqual(MillimetersPerSecondInOneMeterPerSecond, meterpersecond.MillimetersPerSecond, MillimetersPerSecondTolerance);
         }
 
         [Test]
@@ -69,6 +72,7 @@ public void FromValueAndUnit()
             Assert.AreEqual(1, Speed.From(1, SpeedUnit.Knot).Knots, KnotsTolerance);
             Assert.AreEqual(1, Speed.From(1, SpeedUnit.MeterPerSecond).MetersPerSecond, MetersPerSecondTolerance);
             Assert.AreEqual(1, Speed.From(1, SpeedUnit.MilePerHour).MilesPerHour, MilesPerHourTolerance);
+            Assert.AreEqual(1, Speed.From(1, SpeedUnit.MillimeterPerSecond).MillimetersPerSecond, MillimetersPerSecondTolerance);
         }
 
         [Test]
@@ -80,6 +84,7 @@ public void As()
             Assert.AreEqual(KnotsInOneMeterPerSecond, meterpersecond.As(SpeedUnit.Knot), KnotsTolerance);
             Assert.AreEqual(MetersPerSecondInOneMeterPerSecond, meterpersecond.As(SpeedUnit.MeterPerSecond), MetersPerSecondTolerance);
             Assert.AreEqual(MilesPerHourInOneMeterPerSecond, meterpersecond.As(SpeedUnit.MilePerHour), MilesPerHourTolerance);
+            Assert.AreEqual(MillimetersPerSecondInOneMeterPerSecond, meterpersecond.As(SpeedUnit.MillimeterPerSecond), MillimetersPerSecondTolerance);
         }
 
         [Test]
@@ -91,6 +96,7 @@ public void ConversionRoundTrip()
             Assert.AreEqual(1, Speed.FromKnots(meterpersecond.Knots).MetersPerSecond, KnotsTolerance);
             Assert.AreEqual(1, Speed.FromMetersPerSecond(meterpersecond.MetersPerSecond).MetersPerSecond, MetersPerSecondTolerance);
             Assert.AreEqual(1, Speed.FromMilesPerHour(meterpersecond.MilesPerHour).MetersPerSecond, MilesPerHourTolerance);
+            Assert.AreEqual(1, Speed.FromMillimetersPerSecond(meterpersecond.MillimetersPerSecond).MetersPerSecond, MillimetersPerSecondTolerance);
         }
 
         [Test]
diff --git a/UnitsNet/GeneratedCode/Enums/SpeedUnit.g.cs b/UnitsNet/GeneratedCode/Enums/SpeedUnit.g.cs
index 4c18b9b137..2ef59eec94 100644
--- a/UnitsNet/GeneratedCode/Enums/SpeedUnit.g.cs
+++ b/UnitsNet/GeneratedCode/Enums/SpeedUnit.g.cs
@@ -30,5 +30,6 @@ public enum SpeedUnit
         Knot,
         MeterPerSecond,
         MilePerHour,
+        MillimeterPerSecond,
     }
 }
diff --git a/UnitsNet/GeneratedCode/UnitClasses/Speed.g.cs b/UnitsNet/GeneratedCode/UnitClasses/Speed.g.cs
index 9afbec9a24..4086050605 100644
--- a/UnitsNet/GeneratedCode/UnitClasses/Speed.g.cs
+++ b/UnitsNet/GeneratedCode/UnitClasses/Speed.g.cs
@@ -88,6 +88,14 @@ public double MilesPerHour
             get { return _metersPerSecond/0.44704; }
         }
 
+        /// <summary>
+        ///     Get Speed in MillimetersPerSecond.
+        /// </summary>
+        public double MillimetersPerSecond
+        {
+            get { return _metersPerSecond/0.001; }
+        }
+
         #endregion
 
         #region Static 
@@ -137,6 +145,14 @@ public static Speed FromMilesPerHour(double milesperhour)
             return new Speed(milesperhour*0.44704);
         }
 
+        /// <summary>
+        ///     Get Speed from MillimetersPerSecond.
+        /// </summary>
+        public static Speed FromMillimetersPerSecond(double millimeterspersecond)
+        {
+            return new Speed(millimeterspersecond*0.001);
+        }
+
 
         /// <summary>
         ///     Dynamically convert from value and unit enum <see cref="SpeedUnit" /> to <see cref="Speed" />.
@@ -158,6 +174,8 @@ public static Speed From(double value, SpeedUnit fromUnit)
                     return FromMetersPerSecond(value);
                 case SpeedUnit.MilePerHour:
                     return FromMilesPerHour(value);
+                case SpeedUnit.MillimeterPerSecond:
+                    return FromMillimetersPerSecond(value);
 
                 default:
                     throw new NotImplementedException("fromUnit: " + fromUnit);
@@ -301,6 +319,8 @@ public double As(SpeedUnit unit)
                     return MetersPerSecond;
                 case SpeedUnit.MilePerHour:
                     return MilesPerHour;
+                case SpeedUnit.MillimeterPerSecond:
+                    return MillimetersPerSecond;
 
                 default:
                     throw new NotImplementedException("unit: " + unit);
diff --git a/UnitsNet/GeneratedCode/UnitSystem.Default.g.cs b/UnitsNet/GeneratedCode/UnitSystem.Default.g.cs
index 12b995b38c..802e396605 100644
--- a/UnitsNet/GeneratedCode/UnitSystem.Default.g.cs
+++ b/UnitsNet/GeneratedCode/UnitSystem.Default.g.cs
@@ -1260,6 +1260,11 @@ private static readonly ReadOnlyCollection<UnitLocalization> DefaultLocalization
                             {
                                 new AbbreviationsForCulture("en-US", "mph"),
                             }),
+                        new CulturesForEnumValue((int) SpeedUnit.MillimeterPerSecond,
+                            new[]
+                            {
+                                new AbbreviationsForCulture("en-US", "mm/s"),
+                            }),
                     }),
                 new UnitLocalization(typeof (TemperatureUnit),
                     new[]
diff --git a/UnitsNet/Scripts/UnitDefinitions/Speed.json b/UnitsNet/Scripts/UnitDefinitions/Speed.json
index b0641d6671..bc97fd7afc 100644
--- a/UnitsNet/Scripts/UnitDefinitions/Speed.json
+++ b/UnitsNet/Scripts/UnitDefinitions/Speed.json
@@ -15,6 +15,18 @@
                 }
             ]
         },
+        {
+            "SingularName": "MillimeterPerSecond",
+            "PluralName": "MillimetersPerSecond",
+            "FromUnitToBaseFunc": "x*0.001",
+            "FromBaseToUnitFunc": "x/0.001",
+            "Localization": [
+                {
+                    "Culture": "en-US",
+                    "Abbreviations": ["mm/s"]
+                }
+            ]
+        },
         {
             "SingularName": "FootPerSecond",
             "PluralName": "FeetPerSecond",