How do I find out my motherboard model?

This will directly show you motherboard info:

sudo dmidecode -t 2

or

sudo dmidecode | more

You can also try:

lspci

There's also some great graphical tools that show you not just your motherboard info, but all info about your computer.

1. Hardinfo

   Search for the hardinfo package in the Software Center or run sudo apt-get install hardinfo from the command line. The motherboard make and model can be found on the Devices > DMI page.

   

2. CPU-G - Linux alternative to the popular Windows application CPU-Z. Originally created by ftsamis, it has since been picked up by Atareao Team

   sudo add-apt-repository ppa:atareao/atareao
   sudo apt update
   sudo apt install cpu-g
   

   

3. lshw-gtk – Graphical frontend for lshw command

   

4. PerlMon

   

Non-root user variant

I would like to suggest a variant for the unprivileged users, since it's not always possible to execute commands as root (some users simply cannot and however it is always a good practice to avoid running commands as root when it's not needed) and or there is no intention or possibility to install new programs:

cat /sys/devices/virtual/dmi/id/board_{vendor,name,version}

that it is a short version, shell expanded, of cat /sys/devices/virtual/dmi/id/board_vendor /sys/devices/virtual/dmi/id/board_name /sys/devices/virtual/dmi/id/board_version and gives as a spartan output respectively vendor, name and version:

FUJITSU
D3062-A1
S26361-D3062-A1     

Note:
Inside the path /sys/devices/virtual/dmi/id/ it's possible to find some files with information about BIOS, board (motherboard), chassis... not all are readable by an unprivileged user due to a security or privacy concerns.

Privileged user variant

Of course, e.g, a sudo cat board_serial (that usually is readable only by root, -r--------) or a sudo cat board_* can easily overcame this limit...

...but, maybe, if privileges are available it's more convenient to use dmidecode as suggested in other answers as well.

Below is the version I prefer, due to the compactness of its output:

sudo dmidecode -t 1                   # or 
sudo dmidecode  | grep -A4 '^Base'    # output more short and compact

The previous command with -A3 will show only the first 3 lines and it is the short version for
sudo dmidecode | grep -A4 '^Base Board Information' that should be better to use if in a script.

Example output:

Base Board Information
    Manufacturer: FUJITSU
    Product Name: D3062-A1
    Version: S26361-D3062-A1            
    Serial Number: MySerialNumber(1)

⁽¹⁾ if it is protected for unprivileged users, then maybe it's better to avoid posting it :-)

Ps> The following works fine too sudo lshw | grep -A5 "Mot" (again "Mot" is the short for "Motherboard" and only "Mo" will not filter words as Model or Mobile...), but I find it a little lazier than dmidecode to answer with its output (lshw 0.906s vs dmidecode 0.024s).

You can also use lshw. It is usually run with sudo as that allows it to probe your devices and accurately report back information. Just run

sudo lshw  

and the first entries in the results will detail your system and the motherboard and the bios, like in the example below:

*-core
       description: Motherboard
       product: Aspire 1700
       vendor: acer
       physical id: 0
       version: 0303
       serial: None
*-firmware
          description: BIOS
          vendor: acer
          physical id: 0
          version: 3C13
          date: 05/12/04
          size: 109KiB
          capacity: 448KiB
          capabilities: isa pci pcmcia pnp upgrade shadowing escd cdboot bootselect socketedrom int5printscreen int9keyboard int14serial int17printer int10video acpi usb agp smartbattery biosbootspecification

lshw will give you a lot of other information as well; if you want any particular data in future you can run, for example, sudo lshw -class video to find out about your graphics card. For a listing of the hardware classes lshw analyses, enter sudo lshw -short. For more information on the program, enter man lshw in the terminal or visit the Ubuntu manpages.

As Schweinsteiger has noted, dmidecode is also a useful tool for reporting on motherboard info.

I found the quickest & easiest way to determine the motherboard model on my computer is:

dmesg | grep DMI:

which, for the Gigabyte Z68MA-D2H-B3 in my computer, yields:

dennis ~ $ dmesg | grep DMI:
[    0.000000] DMI: Gigabyte Technology Co., Ltd. Z68MA-D2H-B3/Z68MA-D2H-B3, BIOS F2 04/15/2011