Can I play Civ 5 without having Steam installed?

As said by Brian Schkerke you cannot legally play Civilization5 without steam.

People have legitimate gripes about steam, and these questions come up regularly especially on 2K's official Civilization5 forum (2K Civ5 Forum)

However, since Steam is un-avoidable I find it more productive to offer advice to mitigate the effect steam has on your enjoyment and on your system, for in fact many gripes people have with steam are optional and can be disabled.

• You can disable all push pop-up advertising in steam. Instructions
• You can play Civ5 SinglePlayer/LAN offline without connecting to the steam server.Instructions
• You can disable steam collecting anonymous information about your system/software.Wiki
• You can disable steam from running on startup. Instructions

The four points above cover many reasons people dislike Steam. You will however still need to run the Steam client in the background as Civ5 plays. This may be un-palatable for your tastes but at least it is a 'neutered' version of Steam which does not connect to the internet or use up your system resources.

The disadvantages are

• You cannot save your games on the steam cloud while offline (useful for continuing games at different locations)
• You cannot receive patches for the game while steam is offline
• You cannot have your in game achievements ranked.
• You cannot communicate with your friends on Steam

Which you probably would not want to use anyway if you don't use Steam.

Hope this helps.

FYI: I am new to Steam. I have never used Steam before I bought Civ5 last week.

Legally, installing Civilization 5 requires the installation of Steam. You can put Steam into offline mode after initial authorization/authentication. However, all patches to the game are also deployed through Steam so if, at a later date, you wanted to update due to a bug you would need to re-enable online mode for Steam.

There are ways around the installation of Steam but if you're particular about Steam being installed, I doubt you want to investigate the alternate avenues.