Media Planner is a job title in an advertising agency or media planning and buying agency, responsible for selecting media for advertisement placement on behalf of their clients. The main aim of a Media Planner is to assist their client in achieving business objectives through their advertising budgets by recommending the best possible use of various media platforms available to advertisers. Their roles may include analyzing target audiences, keeping abreast of media developments, reading market trends and understanding motivations of consumers (often including psychology and neuroscience).

Traditionally, the role of the media planner was quite close to that of the Media Buyer, the obvious distinction being that the planner would devise a plan for advertising and the buyer would negotiate with the Media proprietor on things such as rates, copy deadlines, placement, merchandising, etc. The role of the modern media planner is more wide reaching however. Today many agencies are actually eschewing the job title of 'media planner' in favour of titles such as communications planner, brand planner or strategist. This reflects the shift away from 'traditional' media planning to a more holistic approach, with the planner now having to consider (as well as standard above-the-line channels such as TV, print, radio and outdoor) PR, below-the-line channels, in-store, digital media, product placement and other emerging communications channels all for the purpose of ensuring the client's advertising budget is well spent as well as adhering to the overall marketing strategy devised by marketing consultants or the client themselves. Their expanded job scope has thus made greater demands of their time, placing them in immensely pressured situations matched by the states faced by their creative (copywriters and art directors) counterparts.

Though many media planners are housed within ad firms, Initiative Worldwide, Carat, ZenithOptimedia, Starcom, Mindshare and OMD are examples of stand-alone global media planning agencies for general consumer brands. As media opportunities grow increasingly fragmented, greater degrees of specificity and specialization have become expected by advertisers. Specialization within individual vertical industries has become the norm. For example, Communications Media Inc. is known for media planning for the pharmaceutical industry, and would therefore be versed in the complex legality of advertising within that industry. Criterion Global is an international media buyer with expertise in lead-generation media buying, customizing multi-lingual and multi-market media strategy to suit the return on investment objectives of travel, real estate, higher education, and retail brands. Strategic Media, in Washington DC, US specializes in political campaign media buying, which requires special expertise due to legal restrictions on political advertising expenditure and other campaign finance cash-flow regulations.

Additionally, specialization within media type has made the media planning landscape more complex. For example, digital media planners are now heavily recruited by media firms. Future areas of digital specialization with high expected growth rates include: behavioural planning specialists, ad network marketing specialists, social media specialists, and SEO/SEM/PPC experts. The extreme growth of the digital sector has justified the advent of online-only media planning firms, most notably Avenue A/Razorfish and Centro, the latter having managed digital media buying for Barack Obama's successful 2008 Presidential bid in the US.