Free Assemblers
NASM Assembler
The Netwide Assembler v0.98, a free protable downloadable assembler for the Intel 80x86 mircroprocessor series, which uses the traditional INtel instruction mnemonics and syntax. Free download.
RosAsm
The Bottom-Up Assembler for ReactOS includes an assembler, a disassembler, debugger and ide.
flat assembler
The flat assembler is a fast and efficient self-assembling 80x86 assembler for DOS, Windows and Linux operating systems. Currently it supports all 8086-80486/Pentium instructions with MMX, SSE, SSE2, SSE3 and 3DNow! extensions, can produce output in binary, MZ, PE, COFF or ELF format. The flat assembler is self-compilable and the full source code is included.
Lazy Assembler
LZASM is an x86 assembler for DOS and Windows that handles the TASM (Turbo Assembler) IDEAL mode and produces OMF OBJ files.
MASM32
MASM32 is a working development environment for programmers who want to write 32 bit Microsoft Assembler (MASM).
SpAsm Assembler
SpAsm is an Assembler for ReactOS / Win32 PE files production ( Win95/98/NT/2000).
ALINK v1.6
A linker being developed to link object files into executable programs. The ultimate purpose is to write a free and portable linker to go with NASM.
VisualASM
Assembly language IDE for programming with MASM. It is a Win32 program and was written totally in ASM. It features syntax highlighting, a customizable Tools menu, project wizards, addin components to extend and add features, and the familiar multiple do
Win32 + Assembler Source Page
If you are interested in 32-bit programming for Windows 95/98/ME/NT/2000/XP using assembler, you will find everything you need here including an Assembler, Resource Compiler, Linker, Symbolic Debugger, Editor, Help Compiler, Information, Tutorials, Sample
asm68.exe
A cross macro assembler that assembles code for the 680xx using a PC.
CodeX Assembler
CodeX Assembler is a Freeware assembler for x86 platforms that supports in the current version 1.0 and version 2.34 of the Opcode Map the instruction sets of all Intel CPUs up to the Pentium IV as well as the AMD 3D.
Flat assembler 1.46
The flat assembler is a fast and efficient self-assembling 80x86 assembler for DOS, Windows and Linux.
High Level Assembler (HLA)
This is the assembler that goes with the free book/tutorial on the assembly tutorials page.
NewBasic Assembler (NBASM)
The NewBasic Assembler, NBASM, is an x86 assembler and is near MASM 5.1x compatible. NBASM is intended for use by beginners starting to learn assembly.
QLINK
QLINK is a DOS linker and analysis tool designed to link together MS-DOS compatible .OBJ files. According to the website it can replace the MS-DOS LINK.EXE program when producing MS-DOS compatible .EXE and .COM files.
Assembly Studio (IDE)
Full IDE for x86 Assembly Language Programming, featuring TASM/TASM32 support. Designed for Windows XP/2K/NT.