diff --git a/posix.mak b/posix.mak
index 9e34c3f1211..8fb1a71d60f 100644
--- a/posix.mak
+++ b/posix.mak
@@ -13,7 +13,8 @@
 #
 # make BUILD=debug unittest => builds all unittests (for debug) and runs them
 #
-# make DEBUGGER=ddd std/XXXXX.debug => builds the module XXXXX and executes it in the debugger ddd
+# make DEBUGGER=ddd std/XXXXX.debug => builds the module XXXXX and executes it
+#                                      in the debugger ddd
 #
 # make html => makes html documentation
 #
@@ -25,10 +26,10 @@
 ################################################################################
 # Configurable stuff, usually from the command line
 #
-# OS can be linux, win32, win32wine, osx, or freebsd. The system will be
-# determined by using uname
+# OS can be linux, win32, win32wine, osx, freebsd, netbsd or dragonflybsd.
+# The system will be determined by using uname
 
-QUIET:=
+QUIET:=@
 
 DEBUGGER=gdb
 GIT_HOME=https://github.com/dlang
diff --git a/std/datetime/systime.d b/std/datetime/systime.d
index 0c7ccebc159..48fa8325144 100644
--- a/std/datetime/systime.d
+++ b/std/datetime/systime.d
@@ -214,6 +214,22 @@ public:
                            hnsecsToUnixEpoch;
                 }
             }
+            else version(DragonFlyBSD)
+            {
+                import core.sys.dragonflybsd.time : clock_gettime, CLOCK_REALTIME,
+                    CLOCK_REALTIME_FAST, CLOCK_REALTIME_PRECISE, CLOCK_SECOND;
+                static if (clockType == ClockType.coarse)       alias clockArg = CLOCK_REALTIME_FAST;
+                else static if (clockType == ClockType.normal)  alias clockArg = CLOCK_REALTIME;
+                else static if (clockType == ClockType.precise) alias clockArg = CLOCK_REALTIME_PRECISE;
+                else static if (clockType == ClockType.second)  alias clockArg = CLOCK_SECOND;
+                else static assert(0, "Previous static if is wrong.");
+                timespec ts;
+                if (clock_gettime(clockArg, &ts) != 0)
+                    throw new TimeException("Call to clock_gettime() failed");
+                return convert!("seconds", "hnsecs")(ts.tv_sec) +
+                       ts.tv_nsec / 100 +
+                       hnsecsToUnixEpoch;
+            }
             else version(Solaris)
             {
                 static if (clockType == ClockType.second)
diff --git a/std/datetime/timezone.d b/std/datetime/timezone.d
index 4743292c9c5..1a6e3d37d35 100644
--- a/std/datetime/timezone.d
+++ b/std/datetime/timezone.d
@@ -325,10 +325,11 @@ public:
 
         version(Posix)
         {
-            version(FreeBSD)      enum utcZone = "Etc/UTC";
-            else version(NetBSD)  enum utcZone = "UTC";
-            else version(linux)   enum utcZone = "UTC";
-            else version(OSX)     enum utcZone = "UTC";
+            version(FreeBSD)            enum utcZone = "Etc/UTC";
+            else version(NetBSD)        enum utcZone = "UTC";
+            else version(DragonFlyBSD)  enum utcZone = "UTC";
+            else version(linux)         enum utcZone = "UTC";
+            else version(OSX)           enum utcZone = "UTC";
             else static assert(0, "The location of the UTC timezone file on this Posix platform must be set.");
 
             auto tzs = [testTZ("America/Los_Angeles", "PST", "PDT", dur!"hours"(-8), dur!"hours"(1)),
diff --git a/std/experimental/allocator/mallocator.d b/std/experimental/allocator/mallocator.d
index e62b9211e88..8befa436b35 100644
--- a/std/experimental/allocator/mallocator.d
+++ b/std/experimental/allocator/mallocator.d
@@ -278,7 +278,7 @@ struct AlignedMallocator
 
     /**
     Forwards to $(D alignedReallocate(b, newSize, platformAlignment)).
-    Should be used with bocks obtained with `allocate` otherwise the custom
+    Should be used with blocks obtained with `allocate` otherwise the custom
     alignment passed with `alignedAllocate` can be lost.
     */
     @system @nogc nothrow
@@ -375,6 +375,9 @@ version(Posix)
     AlignedMallocator.instance.alignedReallocate(c, 32, 32);
     assert(c.ptr);
 
+    version (DragonFlyBSD) {} else    /* FIXME: Malloc on DragonFly does not return NULL when allocating more than UINTPTR_MAX
+                                       * $(LINK: https://bugs.dragonflybsd.org/issues/3114, dragonfly bug report)
+                                       * $(LINK: https://github.com/dlang/druntime/pull/1999#discussion_r157536030, PR Discussion) */
     assert(!AlignedMallocator.instance.alignedReallocate(c, size_t.max, 4096));
     AlignedMallocator.instance.deallocate(c);
 }
diff --git a/std/file.d b/std/file.d
index d9a8d882c3e..fc0f15b6f70 100644
--- a/std/file.d
+++ b/std/file.d
@@ -1488,6 +1488,7 @@ if (isInputRange!R && !isInfinite!R && isSomeChar!(ElementEncodingType!R))
 // - OS X, where the native filesystem (HFS+) stores filesystem
 //   timestamps with 1-second precision.
 version (FreeBSD) {} else
+version (DragonFlyBSD) {} else
 version (OSX) {} else
 @system unittest
 {
@@ -2779,6 +2780,10 @@ else version (NetBSD)
     {
         return readLink("/proc/self/exe");
     }
+    else version (DragonFlyBSD)
+    {
+        return readLink("/proc/curproc/file");
+    }
     else version (Solaris)
     {
         import core.sys.posix.unistd : getpid;
diff --git a/std/math.d b/std/math.d
index 911d5f1526e..b029c50d375 100644
--- a/std/math.d
+++ b/std/math.d
@@ -7444,6 +7444,34 @@ private real polyImpl(real x, in real[] A) @trusted pure nothrow @nogc
                 ;
             }
         }
+        else version (DragonFlyBSD)
+        {
+            asm pure nothrow @nogc // assembler by W. Bright
+            {
+                // EDX = (A.length - 1) * real.sizeof
+                mov     ECX,A[EBP]              ; // ECX = A.length
+                dec     ECX                     ;
+                lea     EDX,[ECX*8]             ;
+                lea     EDX,[EDX][ECX*4]        ;
+                add     EDX,A+4[EBP]            ;
+                fld     real ptr [EDX]          ; // ST0 = coeff[ECX]
+                jecxz   return_ST               ;
+                fld     x[EBP]                  ; // ST0 = x
+                fxch    ST(1)                   ; // ST1 = x, ST0 = r
+                align   4                       ;
+        L2:     fmul    ST,ST(1)                ; // r *= x
+                fld     real ptr -12[EDX]       ;
+                sub     EDX,12                  ; // deg--
+                faddp   ST(1),ST                ;
+                dec     ECX                     ;
+                jne     L2                      ;
+                fxch    ST(1)                   ; // ST1 = r, ST0 = x
+                fstp    ST(0)                   ; // dump x
+                align   4                       ;
+        return_ST:                              ;
+                ;
+            }
+        }
         else
         {
             static assert(0);
diff --git a/std/parallelism.d b/std/parallelism.d
index 5d3f731dc50..2f2c0e33053 100644
--- a/std/parallelism.d
+++ b/std/parallelism.d
@@ -94,6 +94,10 @@ else version(FreeBSD)
 {
     version = useSysctlbyname;
 }
+else version(DragonFlyBSD)
+{
+    version = useSysctlbyname;
+}
 else version(NetBSD)
 {
     version = useSysctlbyname;
@@ -984,6 +988,10 @@ uint totalCPUsImpl() @nogc nothrow @trusted
         {
             auto nameStr = "hw.ncpu\0".ptr;
         }
+        else version(DragonFlyBSD)
+        {
+            auto nameStr = "hw.ncpu\0".ptr;
+        }
         else version(NetBSD)
         {
             auto nameStr = "hw.ncpu\0".ptr;
diff --git a/std/path.d b/std/path.d
index f999453d006..c896421387e 100644
--- a/std/path.d
+++ b/std/path.d
@@ -3970,7 +3970,7 @@ string expandTilde(string inputPath) nothrow
                     }
 
                     if (errno != ERANGE &&
-                        // On FreeBSD and OSX, errno can be left at 0 instead of set to ERANGE
+                        // On BSD and OSX, errno can be left at 0 instead of set to ERANGE
                         errno != 0)
                         onOutOfMemoryError();
 
diff --git a/std/socket.d b/std/socket.d
index fcbc39db700..361ec73daa3 100644
--- a/std/socket.d
+++ b/std/socket.d
@@ -187,6 +187,14 @@ string formatSocketError(int err) @trusted
             else
                 return "Socket error " ~ to!string(err);
         }
+        else version (DragonFlyBSD)
+        {
+            auto errs = strerror_r(err, buf.ptr, buf.length);
+            if (errs == 0)
+                cs = buf.ptr;
+            else
+                return "Socket error " ~ to!string(err);
+        }
         else version (Solaris)
         {
             auto errs = strerror_r(err, buf.ptr, buf.length);
diff --git a/std/stdio.d b/std/stdio.d
index d647177e28e..79397bac75e 100644
--- a/std/stdio.d
+++ b/std/stdio.d
@@ -63,6 +63,12 @@ version (NetBSD)
     version = HAS_GETDELIM;
 }
 
+version (DragonFlyBSD)
+{
+    version = GENERIC_IO;
+    version = HAS_GETDELIM;
+}
+
 version (Solaris)
 {
     version = GENERIC_IO;
diff --git a/std/system.d b/std/system.d
index 1af5013f2b0..dbc0f846986 100644
--- a/std/system.d
+++ b/std/system.d
@@ -32,6 +32,7 @@ immutable
         osx,       /// Mac OS X
         freeBSD,   /// FreeBSD
         netBSD,    /// NetBSD
+        dragonFlyBSD, /// DragonFlyBSD
         solaris,   /// Solaris
         android,   /// Android
         otherPosix /// Other Posix Systems
@@ -45,6 +46,7 @@ immutable
     else version(OSX)     OS os = OS.osx;
     else version(FreeBSD) OS os = OS.freeBSD;
     else version(NetBSD)  OS os = OS.netBSD;
+    else version(DragonFlyBSD) OS os = OS.dragonFlyBSD;
     else version(Posix)   OS os = OS.otherPosix;
     else static assert(0, "Unknown OS.");